phy: renesas: convert to SPDX identifiers

This patch updates license to use SPDX-License-Identifier
instead of verbose license text.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/phy/renesas/Kconfig

+# SPDX-License-Identifier: GPL-2.0
 #
 # Phy drivers for Renesas platforms
 #

drivers/phy/renesas/Makefile

+# SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_PHY_RCAR_GEN2)		+= phy-rcar-gen2.o
 obj-$(CONFIG_PHY_RCAR_GEN3_PCIE)	+= phy-rcar-gen3-pcie.o
 obj-$(CONFIG_PHY_RCAR_GEN3_USB2)	+= phy-rcar-gen3-usb2.o