testsuite: Use -mnofpu for rx-*-* in ieee testsuite [PR107046]

testsuite: Use -mnofpu for rx-*-* in ieee testsuite [PR107046]

add_options_for_ieee has:
    if { [istarget alpha*-*-*]
         || [istarget sh*-*-*] } {
       return "$flags -mieee"
    }
    if { [istarget rx-*-*] } {
       return "$flags -mnofpu"
    }
but ieee.exp doesn't use add_options_for_ieee, instead it has:
if { [istarget "alpha*-*-*"]
     || [istarget "sh*-*-*"] } then {
  lappend additional_flags "-mieee"
}
among other things (plus -ffloat-store on some arches etc.).

The following patch adds the rx -mnofpu similarly in the hope
of fixing ieee.exp FAILs on rx.

Preapproved in the PR by Jeff, committed to trunk.

2022-12-06  Jakub Jelinek  <jakub@redhat.com>

	PR testsuite/107046
	* gcc.c-torture/execute/ieee/ieee.exp: For rx-*-* append
	-mnofpu.