wireless, libertas: remove redundant NULL tests before calling release_firmware()

release_firmware() tests for, and deals gracefully with, NULL
pointers. Remove redundant explicit tests before calling the function.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/libertas/if_spi.c b/drivers/net/wireless/libertas/if_spi.c
index 50b1ee7..7a5df4f 100644
--- a/drivers/net/wireless/libertas/if_spi.c
+++ b/drivers/net/wireless/libertas/if_spi.c
@@ -1095,10 +1095,8 @@
 		goto out;
 
 out:
-	if (helper)
-		release_firmware(helper);
-	if (mainfw)
-		release_firmware(mainfw);
+	release_firmware(helper);
+	release_firmware(mainfw);
 
 	lbs_deb_leave_args(LBS_DEB_SPI, "err %d\n", err);