kernelconfig_penguin
CONFIG_ARCH_LPC32XX_MII_SUPPORT is not available for the default architecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_ARCH_LPC32XX_MII_SUPPORT.
Result is shown for kernelversion 3.4.99

Check to enable MII support or leave disabled for RMII support

configname: CONFIG_ARCH_LPC32XX_MII_SUPPORT

Linux Kernel Configuration
└─> LPC32XX chip components
└─> Check to enable MII support or leave disabled for RMII support

Say Y here to enable MII support, or N for RMII support. Regardless of
which support is selected, the ethernet interface driver needs to be
selected in the device driver networking section.

The PHY3250 reference board uses RMII, so users of this board should
say N.