cgroup2: port over eBPF device controller from crun

The implementation is based on https://github.com/containers/crun/blob/0.10.2/src/libcrun/ebpf.c

Although ebpf.c is originally licensed under LGPL-3.0-or-later, the author
Giuseppe Scrivano agreed to relicense the file in Apache License 2.0:
https://github.com/opencontainers/runc/issues/2144#issuecomment-543116397

See libcontainer/cgroups/ebpf/devicefilter/devicefilter_test.go for tested configurations.

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

vendor/github.com/cilium/ebpf/asm/alu_string.go

@@ -0,0 +1,107 @@
+// Code generated by "stringer -output alu_string.go -type=Source,Endianness,ALUOp"; DO NOT EDIT.
+
+package asm
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[InvalidSource-255]
+	_ = x[ImmSource-0]
+	_ = x[RegSource-8]
+}
+
+const (
+	_Source_name_0 = "ImmSource"
+	_Source_name_1 = "RegSource"
+	_Source_name_2 = "InvalidSource"
+)
+
+func (i Source) String() string {
+	switch {
+	case i == 0:
+		return _Source_name_0
+	case i == 8:
+		return _Source_name_1
+	case i == 255:
+		return _Source_name_2
+	default:
+		return "Source(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+}
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[InvalidEndian-255]
+	_ = x[LE-0]
+	_ = x[BE-8]
+}
+
+const (
+	_Endianness_name_0 = "LE"
+	_Endianness_name_1 = "BE"
+	_Endianness_name_2 = "InvalidEndian"
+)
+
+func (i Endianness) String() string {
+	switch {
+	case i == 0:
+		return _Endianness_name_0
+	case i == 8:
+		return _Endianness_name_1
+	case i == 255:
+		return _Endianness_name_2
+	default:
+		return "Endianness(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+}
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[InvalidALUOp-255]
+	_ = x[Add-0]
+	_ = x[Sub-16]
+	_ = x[Mul-32]
+	_ = x[Div-48]
+	_ = x[Or-64]
+	_ = x[And-80]
+	_ = x[LSh-96]
+	_ = x[RSh-112]
+	_ = x[Neg-128]
+	_ = x[Mod-144]
+	_ = x[Xor-160]
+	_ = x[Mov-176]
+	_ = x[ArSh-192]
+	_ = x[Swap-208]
+}
+
+const _ALUOp_name = "AddSubMulDivOrAndLShRShNegModXorMovArShSwapInvalidALUOp"
+
+var _ALUOp_map = map[ALUOp]string{
+	0:   _ALUOp_name[0:3],
+	16:  _ALUOp_name[3:6],
+	32:  _ALUOp_name[6:9],
+	48:  _ALUOp_name[9:12],
+	64:  _ALUOp_name[12:14],
+	80:  _ALUOp_name[14:17],
+	96:  _ALUOp_name[17:20],
+	112: _ALUOp_name[20:23],
+	128: _ALUOp_name[23:26],
+	144: _ALUOp_name[26:29],
+	160: _ALUOp_name[29:32],
+	176: _ALUOp_name[32:35],
+	192: _ALUOp_name[35:39],
+	208: _ALUOp_name[39:43],
+	255: _ALUOp_name[43:55],
+}
+
+func (i ALUOp) String() string {
+	if str, ok := _ALUOp_map[i]; ok {
+		return str
+	}
+	return "ALUOp(" + strconv.FormatInt(int64(i), 10) + ")"
+}