ARM: shmobile: mackerel: Conditionally select SMSC_PHY

The mackerel board uses has an SMSC911X ethernet controller which uses an
SMSC phy. Select SMSC_PHY for mackerel if SMSC911X is enabled to make use of the
SMSC-specific phy driver rather than relying on the generic phy driver.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/mach-shmobile/Kconfig

@@ -177,6 +177,7 @@ config MACH_MACKEREL
 	depends on ARCH_SH7372
 	select ARCH_REQUIRE_GPIOLIB
 	select REGULATOR_FIXED_VOLTAGE if REGULATOR
+	select SMSC_PHY if SMSC911X
 	select SND_SOC_AK4642 if SND_SIMPLE_CARD
 	select USE_OF