staging/lustre/llite: fix used uninitialized warning

Got below warning when building with sparc:
drivers/staging/lustre/lustre/llite/file.c: In function 'll_file_aio_write':
drivers/staging/lustre/lustre/llite/file.c:1247:9: warning: 'count' may be used uninitialized in this function [-Wuninitialized]
drivers/staging/lustre/lustre/llite/file.c: In function 'll_file_aio_read':
drivers/staging/lustre/lustre/llite/file.c:1188:9: warning: 'count' may be used uninitialized in this function [-Wuninitialized]

Signed-off-by: Peng Tao <bergwolf@gmail.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>