target-arm: Fix typos in comments

Fix a variety of typos in comments in target-arm files.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@petalogix.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
diff --git a/target-arm/arm-semi.c b/target-arm/arm-semi.c
index 88ca9bb..2495206 100644
--- a/target-arm/arm-semi.c
+++ b/target-arm/arm-semi.c
@@ -281,7 +281,7 @@
             return len - ret;
         }
     case TARGET_SYS_READC:
-       /* XXX: Read from debug cosole. Not implemented.  */
+       /* XXX: Read from debug console. Not implemented.  */
         return 0;
     case TARGET_SYS_ISTTY:
         if (use_gdb_syscalls()) {