wan: dscc4: use msecs_to_jiffies for conversions

API compliance scanning with coccinelle flagged:
./drivers/net/wan/dscc4.c:1036:1-33:
        WARNING: timeout (10) seems HZ dependent
./drivers/net/wan/dscc4.c:554:2-34:
        WARNING: timeout (10) seems HZ dependent
./drivers/net/wan/dscc4.c:599:2-34:
        WARNING: timeout (10) seems HZ dependent

Numeric constants passed to schedule_timeout_*() make the effective
timeout HZ dependent which does not seem to be the intent here.
Fixed up by converting the constant to jiffies with msecs_to_jiffies(),
passing 100ms (assuming HZ==100 in the original code).

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