irda: use msecs_to_jiffies for conversion to jiffies

API compliance scanning with coccinelle flagged:
./net/irda/timer.c:63:35-37: use of msecs_to_jiffies probably perferable

Converting milliseconds to jiffies by "val * HZ / 1000" technically
is not a clean solution as it does not handle all corner cases correctly.
By changing the conversion to use msecs_to_jiffies(val) conversion is
correct in all cases. Further the () around the arithmetic expression
was dropped.

Patch was compile tested for x86_64_defconfig + CONFIG_IRDA=m

Patch is against 4.1-rc4 (localversion-next is -next-20150522)

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>