wlan: Uninitialized bits in Capabilities Field of RSN IE

When the PMF (802.11w) feature is not compiled in
the driver (WLAN_FEATURE_11W is not enabled),
the MFPR and MFPC bits in the Capabilities Field
of the RSN IE will not be initialized when constructing
an RSN IE for frames like Association Request.

This is fixed so that these bits are initialized regardless
of whether WLAN_FEATURE_11W is enabled or
not.

Change-Id: I141eebcd9cd4ccebdb9509dd0aa7f487ad5cd61b
CRs-Fixed: 554610