memstick: drivers/memstick/host/jmb38x_ms.c: suppress uninitialized var warning

drivers/memstick/host/jmb38x_ms.c: In function 'jmb38x_ms_transfer_data':
drivers/memstick/host/jmb38x_ms.c:294: warning: 'p_off' may be used uninitialized in this function

Cc: Alex Dubov <oakad@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>