feat(console_log): add FFA_CONSOLE_LOG ABI

Add implementation-defined FFA_CONSOLE_LOG_32/64 ABIs.

Input parameters:
w0/x0 - FFA_CONSOLE_LOG_32/64
w1/x1 - Character count
w2/x2-w7/x7 - 24 or 48 characters depending upon whether a SMC32 or
SMC64 FID was used.

Output parameters in case of success:
w0/x0 - FFA_SUCCESS

Output parameters in case of error:
w0/x0 - FFA_ERROR
w2/x2 - NOT_SUPPORTED: ABI is not implemented
        INVALID_PARAMETERS: Parameters are incorrectly encoded

Signed-off-by: Maksims Svecovs <maksims.svecovs@arm.com>
Change-Id: Ic38d354d736cc7691010ab6d7dbcc42a69ef7c61
diff --git a/src/arch/aarch64/hypervisor/handler.c b/src/arch/aarch64/hypervisor/handler.c
index 4bd8a3b..fc3c324 100644
--- a/src/arch/aarch64/hypervisor/handler.c
+++ b/src/arch/aarch64/hypervisor/handler.c
@@ -631,6 +631,10 @@
 	case FFA_INTERRUPT_32:
 		*args = plat_ffa_delegate_ffa_interrupt(current, next);
 		return true;
+	case FFA_CONSOLE_LOG_32:
+	case FFA_CONSOLE_LOG_64:
+		*args = api_ffa_console_log(*args, current);
+		return true;
 	}
 
 	return false;