lib: optee: remove the duplicate CONFIG_OPTEE

The configuration CONFIG_OPTEE is defined 2 times:
1- in lib/optee/Kconfig for support of OPTEE images loaded by bootm command
2- in drivers/tee/optee/Kconfig for support of OP-TEE driver.

It is abnormal to have the same CONFIG define for 2 purpose;
and it is difficult to managed correctly their dependencies.

Moreover CONFIG_SPL_OPTEE is defined in common/spl/Kconfig
to manage OPTEE image load in SPL.

This definition causes an issue with the macro CONFIG_IS_ENABLED(OPTEE)
to test the availability of the OP-TEE driver.

This patch cleans the configuration dependency with:
- CONFIG_OPTEE_IMAGE (renamed) => support of OP-TEE image in U-Boot
- CONFIG_SPL_OPTEE_IMAGE (renamed) => support of OP-TEE image in SPL
- CONFIG_OPTEE (same) => support of OP-TEE driver in U-Boot
- CONFIG_OPTEE_LIB (new) => support of OP-TEE library

After this patch, the macro have the correct behavior:
- CONFIG_IS_ENABLED(OPTEE_IMAGE) => Load of OP-TEE image is supported
- CONFIG_IS_ENABLED(OPTEE) => OP-TEE driver is supported

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index 34f6fc2..8a8a971 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -1263,11 +1263,11 @@
 	  Enable access to the AM33xx RTC and select the external 32kHz clock
 	  source.
 
-config SPL_OPTEE
-	bool "Support OP-TEE Trusted OS"
+config SPL_OPTEE_IMAGE
+	bool "Support OP-TEE Trusted OS image in SPL"
 	depends on ARM
 	help
-	  OP-TEE is an open source Trusted OS  which is loaded by SPL.
+	  OP-TEE is an open source Trusted OS which is loaded by SPL.
 	  More detail at: https://github.com/OP-TEE/optee_os
 
 config SPL_OPENSBI