boot/optee-os: add support to build with python-pillow

Some specific versions of OP-TEE need the python-pillow module on the
host to build support for the TUI (Trusted User Interface) feature.

To allow building such OP-TEE versions, this commit adds the option
BR2_TARGET_OPTEE_OS_NEEDS_PYTHON_PILLOW which when enabled ensures
that host-python-pillow is built before OP-TEE.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

boot/optee-os/Config.in

@@ -72,6 +72,13 @@ config BR2_TARGET_OPTEE_OS_NEEDS_PYTHON_CRYPTOGRAPHY
 	  python-cryptography. Select this option if optee-os needs
 	  python-cryptography to be built.
 
+config BR2_TARGET_OPTEE_OS_NEEDS_PYTHON_PILLOW
+	bool "OP-TEE OS needs host-python-pillow"
+	help
+	  Some specific OP-TEE OS versions may use python-pillow to
+	  build the Trusted User Interface feature.  Select this
+	  option if optee-os need python-pillow to be built.
+
 config BR2_TARGET_OPTEE_OS_CORE
 	bool "Build core"
 	default y

boot/optee-os/optee-os.mk

@@ -29,6 +29,10 @@ else
 OPTEE_OS_DEPENDENCIES += host-python-pycryptodomex
 endif
 
+ifeq ($(BR2_TARGET_OPTEE_OS_NEEDS_PYTHON_PILLOW),y)
+OPTEE_OS_DEPENDENCIES += host-python-pillow
+endif
+
 ifeq ($(BR2_TARGET_OPTEE_OS_NEEDS_DTC),y)
 OPTEE_OS_DEPENDENCIES += host-dtc
 endif