Use the test_fp_ctl() to test the floating-point control word
for validity and use restore_fp_ctl() to set it in load_sigregs.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>