wl12xx: fix compilation error when CONFIG_PM is not set

There was a compilation error when PM is not enabled:

  CC [M]  drivers/net/wireless/wl12xx/main.o
drivers/net/wireless/wl12xx/main.c:3653: error: unknown field 'suspend' specified in initializer
drivers/net/wireless/wl12xx/main.c:3653: warning: initialization from incompatible pointer type
drivers/net/wireless/wl12xx/main.c:3654: error: unknown field 'resume' specified in initializer
drivers/net/wireless/wl12xx/main.c:3654: warning: initialization from incompatible pointer type

Fix this by adding #ifdef's in the appropriate places.

Cc: Eliad Peller <eliad@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>