thumb: Fix a typo in a comment

Change-Id: Ic318be9d74a95793abc41501fe563164de53a6d7

build/make/thumb.pm

@@ -24,7 +24,7 @@ sub FixThumbInstructions($$)
     # with left shift, addition and a right shift (to restore the
     # register to the original value). Currently the right shift
     # isn't necessary in the code base since the values in these
-    # registers aren't used, but doing the shift for consitency.
+    # registers aren't used, but doing the shift for consistency.
     # This converts instructions such as "add r12, r12, r5, lsl r4"
     # into the sequence "lsl r5, r4", "add r12, r12, r5", "lsr r5, r4".
     s/^(\s*)(add)(\s+)(r\d+),\s*(r\d+),\s*(r\d+),\s*lsl (r\d+)/$1lsl$3$6, $7\n$1$2$3$4, $5, $6\n$1lsr$3$6, $7/g;