brcm80211: smac: rename struct si_info field pbus to pcibus

When moving to bcma usage there are two busses in play. The pci bus
connecting the device to the host and the bcma bus connecting the
cores in the device. To distinguish this the attribute pbus has been
renamed to a more explicit name, ie. pcibus.

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>