phy: renesas: phy-rcar-gen2: use select for GENERIC_PHY

Change the last "depends on GENERIC_PHY" to use select, like the
other 170+ Kconfig users do. This can help prevent circular
dependency issues.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Kishon Vijay Abraham I <kishon@kernel.org>
Cc: linux-phy@lists.infradead.org
Link: https://lore.kernel.org/r/20231204234917.23509-1-rdunlap@infradead.orgSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/renesas/Kconfig

@@ -13,7 +13,7 @@ config PHY_R8A779F0_ETHERNET_SERDES
 config PHY_RCAR_GEN2
 	tristate "Renesas R-Car generation 2 USB PHY driver"
 	depends on ARCH_RENESAS
-	depends on GENERIC_PHY
+	select GENERIC_PHY
 	help
 	  Support for USB PHY found on Renesas R-Car generation 2 SoCs.