brcmfmac: initialize variable in brcmf_sdiod_regrl()

In case of an error the variable returned is uninitialized. The caller
will probably check the error code before using it, but better assure
it is set to zero.
Reviewed-by: NHante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: NPieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Signed-off-by: NArend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c

@@ -420,7 +420,7 @@ u8 brcmf_sdiod_regrb(struct brcmf_sdio_dev *sdiodev, u32 addr, int *ret)
 
 u32 brcmf_sdiod_regrl(struct brcmf_sdio_dev *sdiodev, u32 addr, int *ret)
 {
-	u32 data;
+	u32 data = 0;
 	int retval;
 
 	brcmf_dbg(SDIO, "addr:0x%08x\n", addr);