brcmfmac: enable watchdog when bus initialization is complete

Change condition in brcmf_sdio_wd_timer() function to program
watchdog only when in BRCMF_BUS_DATA state. This avoids watchdog
being active during initialization. During initialization the
SDIO save&restore capability is determined which affect the
bus sleep mechanism used in watchdog thread.

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>