ARM: 7740/1: MCPM: prettify debug output

The CPU and cluster numbers (MPIDR affinity levels 0 and 1) may have
at most 8 bits each.
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/common/mcpm_head.S

@@ -32,11 +32,11 @@
 1901:	adr	r0, 1902b
 	bl	printascii
 	mov	r0, r9
-	bl	printhex8
+	bl	printhex2
 	adr	r0, 1903b
 	bl	printascii
 	mov	r0, r10
-	bl	printhex8
+	bl	printhex2
 	adr	r0, 1904b
 	bl	printascii
 #endif