rtlwifi: rtl8192cu: Add routine phy

Add the routine rtlwifi/rtl8192cu/phy.c. Most of the code is included from
rtlwifi/rtl8192c/phy_common.c.

Signed-off-by: George <george0505@realtek.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>