f2fs: introduce is_valid_blkaddr to cleanup codes in ra_meta_pages
f2fs: introduce is_valid_blkaddr to cleanup codes in ra_meta_pages

This patch does cleanup work, it introduces is_valid_blkaddr() to include
verification code for blkaddr with upper and down boundary value which were in
ra_meta_pages previous.

Signed-off-by: Chao Yu <0cc5db7488e13b393f245aa6263acec5e92fdcc5@samsung.com>
Signed-off-by: Jaegeuk Kim <71255387a32c360dfbe6dfb7aaeb123bf1dc8cb6@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs