sparc32: fix warning in floopy glue

Fix following warning:
arch/sparc/include/asm/floppy_32.h:342:5: warning: 'op' may be used uninitialized in this function

The warning are legitimite and we can end up using op uninitialized.
This fixes build with my gcc on UP.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>