Kbuild: Always use $(PHASE_)

It is confusing to have both "$(PHASE_)" and "$(XPL_)" be used in our
Makefiles as part of the macros to determine when to do something in our
Makefiles based on what phase of the build we are in. For consistency,
bring this down to a single macro and use "$(PHASE_)" only.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index 268116f..22b675f 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -11,19 +11,19 @@
 obj-$(CONFIG_CMD_GO) += boot.o
 obj-y	+= cache.o
 obj-$(CONFIG_SIFIVE_CACHE) += sifive_cache.o
-ifeq ($(CONFIG_$(XPL_)RISCV_MMODE),y)
-obj-$(CONFIG_$(XPL_)RISCV_ACLINT) += aclint_ipi.o
+ifeq ($(CONFIG_$(PHASE_)RISCV_MMODE),y)
+obj-$(CONFIG_$(PHASE_)RISCV_ACLINT) += aclint_ipi.o
 obj-$(CONFIG_ANDES_PLICSW) += andes_plicsw.o
 else
 obj-$(CONFIG_SBI) += sbi.o
 obj-$(CONFIG_SBI_IPI) += sbi_ipi.o
 endif
 obj-y	+= interrupts.o
-ifeq ($(CONFIG_$(XPL_)SYSRESET),)
+ifeq ($(CONFIG_$(PHASE_)SYSRESET),)
 obj-y	+= reset.o
 endif
 obj-y   += setjmp.o
-obj-$(CONFIG_$(XPL_)SMP) += smp.o
+obj-$(CONFIG_$(PHASE_)SMP) += smp.o
 obj-$(CONFIG_XPL_BUILD)	+= spl.o
 obj-y   += fdt_fixup.o
 obj-$(CONFIG_$(SPL)CMD_BDI) += bdinfo.o