wl1271: fix timeout in wl1271_top_reg_read

I noticed a timeout bug in

/drivers/net/wireless/wl12xx/wl1271_spi.c

In the current code you cannot tell why you exited
the "poll for data ready" do-while loop if exiting
was done after the last possible loop.

Then timeout==0 regardless of (val & OCP_READY_MASK) or
!(val & OCP_READY_MASK), leading to possible false timeout...

Simple correction could be decreasing timeout after checking
for !(val & OCP_READY_MASK), not before

(Manually converted from email to an actual patch by me. -- JWL)
Reported-by: N"Juha Leppanen" <juha_motorsportcom@luukku.com>
Signed-off-by: N"Juha Leppanen" <juha_motorsportcom@luukku.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/wl12xx/wl1271_spi.c

@@ -397,8 +397,7 @@ u16 wl1271_top_reg_read(struct wl1271 *wl, int addr)
 	/* poll for data ready */
 	do {
 		val = wl1271_spi_read32(wl, OCP_DATA_READ);
-		timeout--;
-	} while (!(val & OCP_READY_MASK) && timeout);
+	} while (!(val & OCP_READY_MASK) && --timeout);
 
 	if (!timeout) {
 		wl1271_warning("Top register access timed out.");