Instead of defining DWARF register to string table in dwarf-regs-table.h
and dwarf-regs.c, use a common table in dwarf-regs-table.h.

Ensure that the DWARF register table is up-to-date with
http://refspecs.linuxfoundation.org/ELF/zSeries/lzsabi0_s390/x1542.html.

For unwinding with libdw, also ensure to correctly setup the DWARF
register frame according to the register mappings.  Currently, libdw
supports up to 32 registers only.
Suggested-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-and-tested-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>