ROMFS: Advance destination buffer pointer when reading from a blockdev
ROMFS: Advance destination buffer pointer when reading from a blockdev

RomFS should advance the destination buffer pointer when reading data from a
blockdev source (the data may be split over multiple blocks, each requiring its
own sb_read() call).  Without this, all the data is copied to the beginning of
the output buffer.

Signed-off-by: David Howells <ebac1d06c1688626821bb0e574a037a7a5354e49@redhat.com>
Tested-by: Michal Simek <3a191dd2be46e826fee926d532b136ed65cb5318@monstr.eu>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas