brcmfmac: change parameter in brcmf_add_if() function

The brcmf_add_if() function had a struct device as parameter
to accomodate the bus specific code to use this function. The
driver has been reworked so the bus specific code does not need
this function. Better replace the parameter with a more specific
driver object, ie. struct brcmf_pub.

Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Hante Meuleman <meuleman@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>