global: Rename SPL_ to XPL_

Use XPL_ as the symbol to indicate an SPL build. This means that SPL_ is
no-longer set.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index 7a2b764..c35f929 100644
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -8,8 +8,8 @@
 obj-y += rockchip/
 obj-y += socionext/
 
-obj-$(CONFIG_$(SPL_)PHY) += phy-uclass.o
-obj-$(CONFIG_$(SPL_)NOP_PHY) += nop-phy.o
+obj-$(CONFIG_$(XPL_)PHY) += phy-uclass.o
+obj-$(CONFIG_$(XPL_)NOP_PHY) += nop-phy.o
 obj-$(CONFIG_MIPI_DPHY_HELPERS) += phy-core-mipi-dphy.o
 obj-$(CONFIG_AB8500_USB_PHY) += phy-ab8500-usb.o
 obj-$(CONFIG_APPLE_ATCPHY) += phy-apple-atc.o
@@ -19,7 +19,7 @@
 obj-$(CONFIG_BCM6368_USBH_PHY) += bcm6368-usbh-phy.o
 obj-$(CONFIG_BCM_SR_PCIE_PHY) += phy-bcm-sr-pcie.o
 obj-$(CONFIG_PHY_SANDBOX) += sandbox-phy.o
-obj-$(CONFIG_$(SPL_)PIPE3_PHY) += ti-pipe3-phy.o
+obj-$(CONFIG_$(XPL_)PIPE3_PHY) += ti-pipe3-phy.o
 obj-$(CONFIG_AM654_PHY) += phy-ti-am654.o
 obj-$(CONFIG_STI_USB_PHY) += sti_usb_phy.o
 obj-$(CONFIG_PHY_RCAR_GEN2) += phy-rcar-gen2.o
diff --git a/drivers/phy/cadence/Makefile b/drivers/phy/cadence/Makefile
index af63b32..e0da41c 100644
--- a/drivers/phy/cadence/Makefile
+++ b/drivers/phy/cadence/Makefile
@@ -1,2 +1,2 @@
-obj-$(CONFIG_$(SPL_)PHY_CADENCE_SIERRA)	+= phy-cadence-sierra.o
-obj-$(CONFIG_$(SPL_)PHY_CADENCE_TORRENT) += phy-cadence-torrent.o
+obj-$(CONFIG_$(XPL_)PHY_CADENCE_SIERRA)	+= phy-cadence-sierra.o
+obj-$(CONFIG_$(XPL_)PHY_CADENCE_TORRENT) += phy-cadence-torrent.o
diff --git a/drivers/phy/ti/Makefile b/drivers/phy/ti/Makefile
index 873ddbf..699901f 100644
--- a/drivers/phy/ti/Makefile
+++ b/drivers/phy/ti/Makefile
@@ -1 +1 @@
-obj-$(CONFIG_$(SPL_)PHY_J721E_WIZ)	+= phy-j721e-wiz.o
+obj-$(CONFIG_$(XPL_)PHY_J721E_WIZ)	+= phy-j721e-wiz.o