docs(qemu): mention a55 in list of v8.2 cores

Change-Id: Ib3a1711be323023cf111373111f39038fa23fb6f
Signed-off-by: Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org>
diff --git a/plat/qemu/common/common.mk b/plat/qemu/common/common.mk
index b23f7fd..020dc1f 100644
--- a/plat/qemu/common/common.mk
+++ b/plat/qemu/common/common.mk
@@ -32,7 +32,7 @@
 
 # Cpu core architecture level:
 # v8.0: a53, a57, a72
-# v8.2: a76, n1
+# v8.2: a55, a76, n1
 # v8.4: v1
 # v9.0: a710, n2
 #