boot/uboot/uboot.mk: fix zynqmp without pmufw

Commit d07e6b70 (boot/uboot/uboot.mk: add pmufw.elf support) broke
configurations where the UBOOT_ZYNQMP_PMUFW was blank. Previously it
would set the U-Boot CONFIG_PMUFW_INIT_FILE to the blank string, but now
it will set it to ".bin" which causes U-Boot to fail to build.

Signed-off-by: Brandon Maier <brandon.maier@collins.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Brandon Maier <brandon.maier@collins.com>
Reviewed-by: Neal Frager <neal.frager@amd.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit 13dc57c94f9f394441b6faeb864aefd2b8ed08ab)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

boot/uboot/uboot.mk

@@ -395,8 +395,9 @@ UBOOT_ZYNQMP_PMUFW_BASENAME = $(basename $(UBOOT_ZYNQMP_PMUFW_PATH))
 
 define UBOOT_ZYNQMP_KCONFIG_PMUFW
 	$(if $(filter %.elf,$(UBOOT_ZYNQMP_PMUFW_PATH)),
-		objcopy -O binary -I elf32-little $(UBOOT_ZYNQMP_PMUFW_BASENAME).elf $(UBOOT_ZYNQMP_PMUFW_BASENAME).bin)
-	$(call KCONFIG_SET_OPT,CONFIG_PMUFW_INIT_FILE,"$(UBOOT_ZYNQMP_PMUFW_BASENAME).bin")
+		objcopy -O binary -I elf32-little $(UBOOT_ZYNQMP_PMUFW_BASENAME).elf $(UBOOT_ZYNQMP_PMUFW_BASENAME).bin
+		$(call KCONFIG_SET_OPT,CONFIG_PMUFW_INIT_FILE,"$(UBOOT_ZYNQMP_PMUFW_BASENAME).bin"),
+		$(call KCONFIG_SET_OPT,CONFIG_PMUFW_INIT_FILE,"$(UBOOT_ZYNQMP_PMUFW_PATH)"))
 endef
 
 UBOOT_ZYNQMP_PM_CFG = $(call qstrip,$(BR2_TARGET_UBOOT_ZYNQMP_PM_CFG))