[S390] Define new s390 ELF note sections in elf.h

S390 ELF core dump currently only contains the PSW, the general purpose
registers, the floating point registers and the access registers stored
in PRSTATUS/PRFPREG note sections.
For analyzing s390 kernel problems additional registers are important.
In order to be able to include these registers to a kernel ELF core dump,
this patch adds the following five new note sections to elf.h:

* NT_S390_TIMER:   S390 timer register
* NT_S390_TODCMP:  S390 TOD comparator register
* NT_S390_TODPREG: S390 TOD programmable register
* NT_S390_CTRS:    S390 control registers
* NT_S390_PREFIX:  S390 prefix register

The new note sections have been already defined and accepted in the upstream
binutils package.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>