lakitu: Revert "ANDROID: fs: gfs2: fix filler function type"

This reverts commit beda7a698000723a7cedf24f3a92d6097950d815.

The changes are causing compiler error in lakitu-nc:

incompatible pointer types passing 'int (void *, struct page *)'
to parameter of type 'filler_t *' (aka 'int (*)(struct file *, struct page *)')

Also, the patch is reverted by Guenter in:
https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1729064

BUG=b:141332311
TEST=tryjob for lakitu-nc and lakitu
RELEASE_NOTES=None

Change-Id: I7059cae5bd761a1ffb5ecea422ad7915fc0c827e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1815587
Reviewed-by: Xuewei Zhang <xueweiz@google.com>
Commit-Queue: Vaibhav Rustagi <vaibhavrustagi@google.com>
Tested-by: Vaibhav Rustagi <vaibhavrustagi@google.com>