staging: unisys: use schedule_timeout_interruptible()

API consolidation with coccinelle found:
./drivers/staging/unisys/visorbus/periodic_work.c:196:3-19:
        consolidation with schedule_timeout_*() recommended

This is a 1:1 conversion with respect to schedule_timeout() to the
schedule_timeout_interruptible() helper only - so only an API
consolidation to improve readability. The hard coded timeout of 10
jiffies is HZ dependent which it should not be, so it is converted
with msecs_to_jiffies.

Patch was compile tested with x86_64_defconfig + CONFIG_STAGING=y,
CONFIG_UNISYSSPAR=y, CONFIG_UNISYS_VISORBUS=m

Patch is against 4.1-rc5 (localversion-next is -next-20150529)

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>