boot/arm-trusted-firmware: allow additional make targets

Allow specifying additional build targets for ATF.

This might be more useful when using a custom git repository.

For example, when using with the ATF repository from NXP QorIQ,
there is a new build target 'pbl' which is used to build the
pbl binary image. Note that in the specific case of the 'pbl'
target, additional build variables also need to be specified
through BR2_TARGET_ARM_TRUSTED_FIRMWARE_ADDITIONAL_VARIABLES.

Signed-off-by: Francois Gervais <fgervais@distech-controls.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

boot/arm-trusted-firmware/Config.in

@@ -135,6 +135,13 @@ config BR2_TARGET_ARM_TRUSTED_FIRMWARE_UBOOT_BL33_IMAGE
 
 endif
 
+config BR2_TARGET_ARM_TRUSTED_FIRMWARE_ADDITIONAL_TARGETS
+	string "Additional ATF make targets"
+	help
+	  Additional targets for the ATF build
+	  E.G. When using the QorIQ custom ATF repository from NXP,
+	  the target 'pbl' can be used to build the pbl binary.
+
 config BR2_TARGET_ARM_TRUSTED_FIRMWARE_ADDITIONAL_VARIABLES
 	string "Additional ATF build variables"
 	help

boot/arm-trusted-firmware/arm-trusted-firmware.mk

@@ -139,6 +139,9 @@ define ARM_TRUSTED_FIRMWARE_BL31_UBOOT_INSTALL_ELF
 endef
 endif
 
+ARM_TRUSTED_FIRMWARE_MAKE_TARGETS += \
+	$(BR2_TARGET_ARM_TRUSTED_FIRMWARE_ADDITIONAL_TARGETS)
+
 define ARM_TRUSTED_FIRMWARE_BUILD_CMDS
 	$(ARM_TRUSTED_FIRMWARE_BUILD_FIPTOOL)
 	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) $(ARM_TRUSTED_FIRMWARE_MAKE_OPTS) \