brcm80211: smac: remove smatch warnings from brcmsmac code

The patch fixes following smatch warnings:

main.c +2902 brcms_b_read_objmem(11) info: ignoring unreachable code.
mac80211_if.c +1146 brcms_suspend(8) error: we previously assumed 'wl'
could be null (see line 1145)
srom.c +641 _initvars_srom_pci(16) error: potential null dereference
'entry'.  (kzalloc returns null)

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
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: John W. Linville <linville@tuxdriver.com>