staging: brcm80211: remove wl_alloc_dma_resources() function

The function wl_alloc_dma_resources() does not provide any value
for the brcmsmac driver as it only returns true. It has been
removed from the driver.

Reviewed-by: Henry Ptasinski <henryp@broadcom.com>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>