Fix PR92950: Wrong code emitted for movv1qi

Fix PR92950: Wrong code emitted for movv1qi

The backend emits 16 bit memory loads for single element character
vector.  As a result the character will not be right justified in the
GPR.

gcc/ChangeLog:

2019-12-16  Andreas Krebbel  <krebbel@linux.ibm.com>

	PR target/92950
	* config/s390/vector.md ("mov<mode>" for V_8): Replace lh, lhy,
	and lhrl with llc.

gcc/testsuite/ChangeLog:

2019-12-16  Andreas Krebbel  <krebbel@linux.ibm.com>

	PR target/92950
	* gcc.target/s390/vector/pr92950.c: New test.

From-SVN: r279410