fix[script]: Prepend bash with /usr/bin/env

Reported by https://github.com/rockchip-linux/mpp/pull/890

Change-Id: I066dad0e3cef66546994406394daf29df4a67849
Signed-off-by: Herman Chen <herman.chen@rock-chips.com>

merge_static_lib.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 cd $1
 rm -rf mpp/lib'$2$'.a
@@ -7,4 +7,4 @@ SCRIPT=$'CREATE mpp/lib'$2$'.a\n'
 SCRIPT=$SCRIPT$(find . -name '*.a' -exec echo 'ADDLIB {}' \;)
 SCRIPT=$SCRIPT$'\nSAVE\nEND\n'
 
-ar -M <<< $SCRIPT
+ar -M <<< $SCRIPT