Convert CONFIG_PHY_RESET_DELAY to Kconfig

This converts the following to Kconfig:
   CONFIG_PHY_RESET_DELAY

Cc: Ramon Fried <rfried.dev@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/comtrend_ar5315u_ram_defconfig b/configs/comtrend_ar5315u_ram_defconfig
index 45e8b76..9268aea 100644
--- a/configs/comtrend_ar5315u_ram_defconfig
+++ b/configs/comtrend_ar5315u_ram_defconfig
@@ -50,6 +50,7 @@
 CONFIG_DM_SPI_FLASH=y
 CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_SPI_FLASH_MTD=y
+CONFIG_PHY_RESET_DELAY=20
 CONFIG_DM_ETH=y
 CONFIG_BCM6368_ETH=y
 CONFIG_PHY=y