s390/fpu: get rid of MACHINE_HAS_VX

Get rid of MACHINE_HAS_VX and replace it with cpu_has_vx() which is a
short readable wrapper for "test_facility(129)".

Facility bit 129 is set if the vector facility is present. test_facility()
returns also true for all bits which are set in the architecture level set
of the cpu that the kernel is compiled for. This means that
test_facility(129) is a compile time constant which returns true for z13
and later, since the vector facility bit is part of the z13 kernel ALS.

In result the compiled code will have less runtime checks, and less code.

Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

lib/raid6/s390vx.uc

@@ -158,7 +158,7 @@ static void raid6_s390vx$#_xor_syndrome(int disks, int start, int stop,
 
 static int raid6_s390vx$#_valid(void)
 {
-	return MACHINE_HAS_VX;
+	return cpu_has_vx();
 }
 
 const struct raid6_calls raid6_s390vx$# = {