style(expect): normalize debugging messages

A minor style cleanup to the messages printed by the Expect scripts to
make them a bit more consistent and descriptive.

Signed-off-by: Chris Kay <chris.kay@arm.com>
Change-Id: Ibd8ccb4423bd5aaeffc99c2f3602123794dc6200
(cherry picked from commit 78ea2c38582da41eb8f9509a2130e702cdf0f1c9)
diff --git a/expect/trusted-firmware.inc b/expect/trusted-firmware.inc
index fc5af71..d19d7e7 100644
--- a/expect/trusted-firmware.inc
+++ b/expect/trusted-firmware.inc
@@ -14,19 +14,19 @@
 	expect_string "Booting Trusted Firmware"
 
 	expect {
-		"BL1: Booting BL2" { puts "<<BL2 booting>>" }
+		"BL1: Booting BL2" { message "BL2 booting" }
 
 		# Catch all 3 possible BL2 loading error messages, namely:
 		#   "Failure in pre image load handling of BL2"
 		#   "Failed to load BL2 firmware."
 		#   "Failure in post image load handling of BL2"
 		-re "Fail.*load.*BL2" {
-			puts "<<BL2 loading error>>"
+			message "BL2 loading error"
 			exit_uart -1
 		}
 	    }
 
 	expect_string "BL1: Booting BL31"
 } else {
-	puts "<<Skipping early boot messages from BL1 and BL2>>"
+	message "Skipping early boot messages from BL1 and BL2"
 }