binutils: backport first section frag alignment fix for xtensa gas

This fixes the following build error often seen during linux kernel
linking step with relaxation enabled:

  dangerous relocation: call8: misaligned call target: (.text.unlikely+0x63)

Backported from: a35d5e823fdfe8a6e7e05ca8e3fb8bb5697335b1
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>