rtlwifi: Move common parts of rtl8192ce/phy.c

Move common routines from rtlwifi/rtl8192ce/phy.c and .../rtl8192cu/phy.c
into rtlwifi/rtl8192c/phy_common.c.
Signed-off-by: NLarry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>