staging: brcm80211: separate hndpmu functionality for brcmsmac driver

The hndpmu source file has functions for brcmfmac and brcmsmac driver
but it turns out that on function level there is no reuse so for
the brcmsmac its set of functions now reside in wlc_pmu.c.

Cc: devel@linuxdriverproject.org
Cc: linux-wireless@vger.kernel.org
Cc: Brett Rudley <brudley@broadcom.com>
Cc: Henry Ptasinski <henryp@broadcom.com>
Cc: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>