ANDROID: 16K: Handle pgoff > file_size for shmem and file backed VMAs

VMAs can be created to be larger than the backing file: See [1]
(This is also true for shmem backed VMAs.)

Faulting off the end of a file will result in SIGBUS since there
is no file page for the given file offset.

shmem pages live in page cache or swap cache. Looking up a page cache
page with an index (pgoff) beyond the file is invalid and will result
in shmem_get_folio_gfp() returning -EINVAL.

Insert fixup anon vmas for such file backed and shmem backed VMAs,
to prevent the invalid faults in emulated 16kB mode.

Although the 16K emulators currently use ext4 for the /data partition,
also handle the case for f2fs which overrides the default filemap_fault
with f2f2_filemap_fault().

[1] https://r.android.com/2967716



Bug: 355274435
Test: adb root && adb shell &&
      adb shell cp /system/bin/strace /dev/ &&
      adb shell /dev/strace -h
Change-Id: Iede02e82fc5958b3aafaf75383404f2f7f59bb23
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>