fix[allocator]: Fix misc buffer group flag issue

The default misc buffer group do not have the flag. We need to seperate
the default misc group with different flag.

Signed-off-by: Herman Chen <herman.chen@rock-chips.com>
Change-Id: I14941eedfe9c06ec978a12061ba33e12495aa038

osal/mpp_allocator_api.h

@@ -12,6 +12,7 @@ typedef MPP_RET (*OsAllocatorFunc)(void *ctx, MppBufferInfo *info);
 
 typedef struct os_allocator_t {
     MppBufferType type;
+    const char *name;
 
     MPP_RET (*open)(void **ctx, size_t alignment, MppAllocFlagType flags);
     MPP_RET (*close)(void *ctx);