s390: Align letter case of instruction descriptions

Change the bitwise operations names "and" and "or" to lower case. Change
the register name abbreviations "FPR", "GR", and "VR" to upper case.

opcodes/
	* s390-opc.txt: Align letter case of instruction descriptions.

Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Reviewed-by: Andreas Krebbel <krebbel@linux.ibm.com>