ARM: shmobile: Lager: conditionally select CONFIG_MICREL_PHY

Now that support for KSZ8041RNLI is added to the Micrel PHY driver and we intend
to support PHY IRQs on the Lager board, we have to enable the Micrel driver.
Do this by selecting CONFIG_MICREL_PHY for Lager if CONFIG_SH_ETH is enabled.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>