global: Rename SPL_TPL_ to PHASE_

Use PHASE_ as the symbol to select a particular XPL build. This means
that SPL_TPL_ is no-longer set.

Update the comment in bootstage to refer to this symbol, instead of
SPL_

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile
index 6d4bcd3..a89ee7a 100644
--- a/drivers/clk/imx/Makefile
+++ b/drivers/clk/imx/Makefile
@@ -2,25 +2,25 @@
 #
 # SPDX-License-Identifier: GPL-2.0
 
-obj-$(CONFIG_$(SPL_TPL_)CLK_CCF) += clk-gate2.o clk-pllv3.o clk-pfd.o
-obj-$(CONFIG_$(SPL_TPL_)CLK_IMX6Q) += clk-imx6q.o
+obj-$(CONFIG_$(PHASE_)CLK_CCF) += clk-gate2.o clk-pllv3.o clk-pfd.o
+obj-$(CONFIG_$(PHASE_)CLK_IMX6Q) += clk-imx6q.o
 obj-$(CONFIG_CLK_IMX8) += clk-imx8.o
 
 ifdef CONFIG_CLK_IMX8
 obj-$(CONFIG_IMX8QXP) += clk-imx8qxp.o
 obj-$(CONFIG_IMX8QM) += clk-imx8qm.o
 endif
-obj-$(CONFIG_$(SPL_TPL_)CLK_IMX8MM) += clk-imx8mm.o clk-pll14xx.o \
+obj-$(CONFIG_$(PHASE_)CLK_IMX8MM) += clk-imx8mm.o clk-pll14xx.o \
 				clk-composite-8m.o
-obj-$(CONFIG_$(SPL_TPL_)CLK_IMX8MN) += clk-imx8mn.o clk-pll14xx.o \
+obj-$(CONFIG_$(PHASE_)CLK_IMX8MN) += clk-imx8mn.o clk-pll14xx.o \
 				clk-composite-8m.o
-obj-$(CONFIG_$(SPL_TPL_)CLK_IMX8MP) += clk-imx8mp.o clk-pll14xx.o \
+obj-$(CONFIG_$(PHASE_)CLK_IMX8MP) += clk-imx8mp.o clk-pll14xx.o \
 				clk-composite-8m.o
-obj-$(CONFIG_$(SPL_TPL_)CLK_IMX8MQ) += clk-imx8mq.o clk-pll14xx.o \
+obj-$(CONFIG_$(PHASE_)CLK_IMX8MQ) += clk-imx8mq.o clk-pll14xx.o \
 				clk-composite-8m.o
-obj-$(CONFIG_$(SPL_TPL_)CLK_IMX93) += clk-imx93.o clk-fracn-gppll.o \
+obj-$(CONFIG_$(PHASE_)CLK_IMX93) += clk-imx93.o clk-fracn-gppll.o \
 				clk-gate-93.o clk-composite-93.o
 
-obj-$(CONFIG_$(SPL_TPL_)CLK_IMXRT1020) += clk-imxrt1020.o
-obj-$(CONFIG_$(SPL_TPL_)CLK_IMXRT1050) += clk-imxrt1050.o
-obj-$(CONFIG_$(SPL_TPL_)CLK_IMXRT1170) += clk-imxrt1170.o
+obj-$(CONFIG_$(PHASE_)CLK_IMXRT1020) += clk-imxrt1020.o
+obj-$(CONFIG_$(PHASE_)CLK_IMXRT1050) += clk-imxrt1050.o
+obj-$(CONFIG_$(PHASE_)CLK_IMXRT1170) += clk-imxrt1170.o