staging: brcm80211: remove unused functions from wlc_phy_qmath.c

The phy code only uses a subset of functions in wlc_phy_qmath.c and
the remaining are unused so those have been removed to cleanup the
codebase.

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>