GCC4.6: Squash warnings in yaffs_guts.c

GCC4.6: Squash warnings in yaffs_guts.c

yaffs_guts.c: In function 'yaffs_ReadDataFromFile':
yaffs_guts.c:4461:8: warning: 'chunk' may be used uninitialized in this function
yaffs_guts.c:4462:8: warning: 'start' may be used uninitialized in this function
yaffs_guts.c: In function 'yaffs_WriteDataToFile':
yaffs_guts.c:4581:8: warning: 'chunk' may be used uninitialized in this function
yaffs_guts.c:4582:8: warning: 'start' may be used uninitialized in this function
yaffs_guts.c: In function 'yaffs_ResizeFile':
yaffs_guts.c:4816:8: warning: 'newSizeOfPartialChunk' may be used uninitialized
in this function
yaffs_guts.c:4817:8: warning: 'newFullChunks' may be used uninitialized in this
function

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: William Juul <william.juul@tandberg.com>