[media] si2157: advertise Si2158 A20 firmware

Driver uses that firmware. Add it module firmware list.
Signed-off-by: Antti Palosaari <crope@iki.fi>
Tested-by: Olli Salonen <olli.salonen@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/tuners/si2157.c

@@ -360,3 +360,4 @@ module_i2c_driver(si2157_driver);
 MODULE_DESCRIPTION("Silicon Labs Si2157/Si2158 silicon tuner driver");
 MODULE_AUTHOR("Antti Palosaari <crope@iki.fi>");
 MODULE_LICENSE("GPL");
+MODULE_FIRMWARE(SI2158_A20_FIRMWARE);