brcmfmac: restore mpc before passing scan status to cfg80211

brcmfmac: restore mpc before passing scan status to cfg80211

Before informing cfg80211 about the scan status the device should
be put back in mpc state. If done after user-space may initiate
another (scheduled) scan and fail because scan is still busy as
shown in logging below:

[ 3301.367376] brcmfmac: brcmf_fweh_event_worker event ESCAN_RESULT (69)
[ 3301.377305] brcmfmac: brcmf_fweh_event_worker   version 2 flags 0 status 0
[ 3301.384993] brcmutil: event payload, len=12
[ 3301.389208] 00000000: 0c 00 00 00 6d 00 00 00 34 12 00 00
[ 3301.389214] brcmfmac: brcmf_sdio_kso_control Enter: on=0
[ 3301.402196] brcmfmac: brcmf_inform_bss scanned AP count (0)
[ 3301.407808] brcmfmac: brcmf_notify_escan_complete Enter
[ 3301.413064] brcmfmac: brcmf_notify_escan_complete ESCAN Completed scan: Done
[ 3301.420137] brcmfmac: brcmf_sdio_bus_txctl Enter
[ 3301.420368] brcmfmac: brcmf_cfg80211_sched_scan_start Enter
[ 3301.420370] brcmfmac: brcmf_cfg80211_sched_scan_start:
				Scanning already: status (1)
[ 3301.440190] brcmfmac: brcmf_sdio_kso_control Enter: on=1
[ 3301.448695] brcmfmac: brcmf_sdio_tx_ctrlframe Enter
[ 3301.453662] brcmfmac: brcmf_sdio_bus_rxctl Enter
[ 3301.458326] brcmfmac: brcmf_sdio_isr Enter
[ 3301.462523] brcmfmac: brcmf_sdio_dpc Enter
[ 3301.466632] brcmfmac: brcmf_sdio_readframes Enter
[ 3301.471431] brcmfmac: brcmf_sdio_read_control Enter
[ 3301.476340] brcmfmac: brcmf_set_mpc MPC : 1

Reviewed-by: Hante Meuleman <meuleman@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>