brcm80211: smac: replace ai_corereg() function with ai_cc_reg()

The ai_corereg() function is only used in the driver to safely
access the chipcommon core. The function has been renamed to
ai_cc_reg() removing the need to provide a core index parameter.

Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Alwin Beukers <alwin@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Franky Lin <frankyl@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>