mac80211: initialize variable have_higher_than_11mbit

Clang static analysis reports this warnings

mlme.c:5332:7: warning: Branch condition evaluates to a
  garbage value
    have_higher_than_11mbit)
    ^~~~~~~~~~~~~~~~~~~~~~~

have_higher_than_11mbit is only set to true some of the time in
ieee80211_get_rates() but is checked all of the time.  So
have_higher_than_11mbit needs to be initialized to false.

Fixes: 5d6a1b06

 ("mac80211: set basic rates earlier")
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20211223162848.3243702-1-trix@redhat.com


Signed-off-by: Johannes Berg <johannes.berg@intel.com>