mac80211_hwsim: Replace bogus hrtimer clockid

mac80211_hwsim initializes a hrtimer with clockid
CLOCK_MONOTONIC_RAW. That's not supported.

Use CLOCK_MONOTONIC instead.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>