qcacmn: Fix compilation error when CONFIG_BAND_6GHZ is disabled
Add a static inline definition for wlan_reg_is_range_overlap_6g
when CONFIG_BAND_6GHZ is disabled, to fix the compilation error, that
is seen when CONFIG_BAND_6GHZ is disabled.
Change-Id: I26cf77c029d7d27887c242a1c7c300219c125256
CRs-Fixed: 2817943