aarch64: Fix the hyphenated disassembly comment.

aarch64: Fix the hyphenated disassembly comment.

This patch fixes the following comment.

-  /* The hyphenated form is preferred for disassembly if there are
-     more than two registers in the list, and the register numbers
      are monotonically increasing in increments of one.  */

+  /* The hyphenated form is preferred for disassembly if there is
+     more than one register in the list, and the register numbers
      are monotonically increasing in increments of one.  */