arm_ffa: use debug logs

replace info logs with debug logs

Signed-off-by: Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
Cc: Tom Rini <trini@konsulko.com>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/arch/arm64.ffa.rst b/doc/arch/arm64.ffa.rst
index 325fb80..4ecdc31 100644
--- a/doc/arch/arm64.ffa.rst
+++ b/doc/arch/arm64.ffa.rst
@@ -231,7 +231,7 @@
 Example of boot logs with FF-A enabled
 --------------------------------------
 
-For example, when using FF-A with Corstone-1000 the logs are as follows:
+For example, when using FF-A with Corstone-1000, debug logs enabled, the output is as follows:
 
 ::