Convert CONFIG_OMAP_EHCI_PHY1_RESET_GPIO et al to Kconfig

This converts the following to Kconfig:
   CONFIG_OMAP_EHCI_PHY1_RESET_GPIO
   CONFIG_OMAP_EHCI_PHY2_RESET_GPIO
   CONFIG_OMAP_EHCI_PHY3_RESET_GPIO

To do this, we also introduce CONFIG_HAS_CONFIG_OMAP_EHCI_PHYn_RESET_GPIO
options to get setting the GPIO number.

Signed-off-by: Tom Rini <trini@konsulko.com>