rtlwifi: rtl8192ce: Refactor rtl8192ce/fw

Make rtlwifi/rtl8192ce/fw.{h,c} match what will be needed for
rtlwifi/rtl8192cu.{h,c}.

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