iwlwifi: mvm: rs: move rs_program_fix_rate to cleanup ifdefs

Move rs_program_fix_rate right before it's caller where we're
already in the context of an ifdef CPTCFG_MAC80211_DEBUGFS so
we can get rid of the extra ifdefs surrounding the original
location.

Signed-off-by: Eyal Shapira <eyal@wizery.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>