wlan: Fix mismatch between format specifiers and vos_trace_msg

VOS_TRACE log statement should NOT have comma between
the two strings. This prevents the strings from being
concatenated as a single format string, and in fact
the 2nd string then provides the parameter for the initial "%s"
in the format string that is supposed to be filled by __func__.

Change-Id: I26d15615963874662c71ca8d97d2479f041df2bd
CRs-Fixed: 568847