(arm_is_longcall_p): Update comment describing this funciton's behaviour.

  Return true when the current function has a section attribute and
  -mlong-calls is in effect.
(ARM_DECLARE_FUNCTION_SIZE): Do not set the short-call marker when
  -mlong-calls is in effect and the function has a section attribute.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@85796 138bc75d-0d04-0410-961f-82ee72b054a4