Summary:
1.Add configuration to allocate memory from the specified section
2.Replace all memory operations (kmm_) in the vfs with
fs_heap_. When FS_HEAPSIZE > 0, memory is requested for the file system by specifying a configured heap location. By default (i.e. FS_HEAPSIZE=0) fs_heap_ is equivalent to kmm_
Signed-off-by: chenrun1 <chenrun1@xiaomi.com>
