Compiler Attributes: Add continue in comment

Add "continue;" for switch/case block according to Doc[1]

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-throughSigned-off-by: Wei Ming Chen <jj251510319013@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

include/linux/compiler_attributes.h

@@ -199,6 +199,7 @@
  * must end with any of these keywords:
  *   break;
  *   fallthrough;
+ *   continue;
  *   goto <label>;
  *   return [expression];
  *