wl1271: fix timeout in wl1271_top_reg_read

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: "Juha Leppanen" <juha_motorsportcom@luukku.com>
Signed-off-by: "Juha Leppanen" <juha_motorsportcom@luukku.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>