brcmfmac: correct detection of save&restore device capability

The detection of the save&restore capability in brcmf_sdio_sr_capable()
is only valid for certain chipsets. This patch should cover it for all
chipsets currently supported.

Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Franky Lin <frankyl@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>