staging: brcm80211: fix potential null pointer access handling ucode buffer

Allocation of buffer in function wl_ucode_init_buf can fail. This was
signalled by an error message, but code continued to access the null
pointer. This is now avoided by jumping to failure label.
Reviewed-by: NRoland Vossen <rvossen@broadcom.com>
Reviewed-by: NBrett Rudley <brudley@broadcom.com>
Reviewed-by: NHenry Ptasinski <henryp@broadcom.com>
Signed-off-by: NArend van Spriel <arend@broadcom.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/brcm80211/brcmsmac/wl_mac80211.c

@@ -1707,6 +1707,7 @@ int wl_ucode_init_buf(struct wl_info *wl, void **pbuf, u32 idx)
 				if (*pbuf == NULL) {
 					WL_ERROR("fail to alloc %d bytes\n",
 						 hdr->len);
+					goto fail;
 				}
 				bcopy(pdata, *pbuf, hdr->len);
 				return 0;
@@ -1715,6 +1716,7 @@ int wl_ucode_init_buf(struct wl_info *wl, void **pbuf, u32 idx)
 	}
 	WL_ERROR("ERROR: ucode buf tag:%d can not be found!\n", idx);
 	*pbuf = NULL;
+fail:
 	return -1;
 }