brcmfmac: remove firmware list from USB driver

brcmfmac: remove firmware list from USB driver

The USB driver was using a list for firmware info that was
used in suspend/resume scenario. Now that brcmfmac is using
the asynchronous firmware request this is no longer needed.

Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Daniel (Deognyoun) Kim <dekim@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>