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/sfr_nb4-ser_ram_defconfig b/configs/sfr_nb4-ser_ram_defconfig
index 5caad90..e97c1f0 100644
--- a/configs/sfr_nb4-ser_ram_defconfig
+++ b/configs/sfr_nb4-ser_ram_defconfig
@@ -53,6 +53,7 @@
 CONFIG_SYS_FLASH_CFI=y
 CONFIG_SYS_MAX_FLASH_BANKS_DETECT=y
 CONFIG_PHY_FIXED=y
+CONFIG_PHY_RESET_DELAY=20
 CONFIG_DM_ETH=y
 CONFIG_BCM6348_ETH=y
 CONFIG_PHY=y