brcmfmac: reset suspend flag upon sdio suspend failure

The suspend callback first sets the suspend flag used in the driver
but after that the actual suspend is done, which may fail. Reset the
flag upon suspend failure.

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