rtlwifi: rtl8192cu: Convert driver to use rtl_process_phyinfo()

Remove routine _rtl92c_process_phyinfo() by using the equivalent routine
in driver rtlwifi.

This change also allows the removal of 5 additional routines from rtl8192cu.

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