wl12xx: remove some dead code in wl1271_plt_init()

"ret" has already been checked at this point, and we don't need to check
it again.  This was left around from a previous patch 49d750ca


"wl12xx: 1281/1283 support - New radio structs and functions".

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>