ANDROID: sdcardfs: make it use new .rename i_op

Since commit 2773bf00 ("fs: rename "rename2" i_op to "rename""),
syscall rename2 is merged with rename syscall and it broke sdcard_fs
build and we get following build error:

  CC [M]  fs/sdcardfs/inode.o
fs/sdcardfs/inode.c:786:13: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
  .rename  = sdcardfs_rename,
             ^
fs/sdcardfs/inode.c:786:13: note: (near initialization for ‘sdcardfs_dir_iops.rename’)

renameat2 syscall is the same as renameat with an added flags argument
and calling renameat2 with flags=0 is equivalent to calling renameat.

Change-Id: I48f3c76c3af481241188253a76f310670de6bd18
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>