ANDROID: sdcardfs: Add default_normal option

The default_normal option causes mounts with the gid set to
AID_SDCARD_RW to have user specific gids, as in the normal case.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Change-Id: I9619b8ac55f41415df943484dc8db1ea986cef6f
Bug: 64672411
Git-commit: 6c72cab1
Git-repo: https://android.googlesource.com/kernel/common/


Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>