brcm80211: fmac: remove function brcmf_c_init

brcmf_c_init only init brcmf_msg_level used for debug. It's no longer
needed as brcmf_msg_level doesn't cause trouble to multiple instances.

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