Revert "net: cadence: macb: sama7g5_emac: Remove USARIO CLKEN flag"

This reverts commit db40006.

This commit can cause a Devicetree ABI break for older DTS files that rely this
flag for RMII configuration. Adding this back in ensures that the older
DTBs will not break.

Fixes: db40006 ("net: cadence: macb: sama7g5_emac: Remove USARIO CLKEN flag")
Signed-off-by: Ryan Wanner <Ryan.Wanner@microchip.com>
Link: https://patch.msgid.link/20250819163236.100680-1-Ryan.Wanner@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: ryan-wanner

drivers/net/ethernet/cadence/macb_main.c

@@ -5113,7 +5113,8 @@ static const struct macb_config sama7g5_gem_config = {
 
 static const struct macb_config sama7g5_emac_config = {
 	.caps = MACB_CAPS_USRIO_DEFAULT_IS_MII_GMII |
-		MACB_CAPS_MIIONRGMII | MACB_CAPS_GEM_HAS_PTP,
+		MACB_CAPS_USRIO_HAS_CLKEN | MACB_CAPS_MIIONRGMII |
+		MACB_CAPS_GEM_HAS_PTP,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = macb_init,