syncup with Metaware tools w.r.t. new relocations

* include/elf/arc.h: Add new relocations to syncup with Metaware tools

* bfd/elf32-arc.c (elf_arc_reloc_type): Add new relocations to syncup
  with Metaware tools

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Simon Cook <simon.cook@embecosm.com>
Cc: Francois Bedard <Francois.Bedard@synopsys.com>
Cc: jeremy.bennett@embecosm.com <jeremy.bennett@embecosm.com>
Cc: Anton Kolesov <Anton.Kolesov@synopsys.com>
Cc: Claudiu Zissulescu <Claudiu.Zissulescu@synopsys.com>
Cc: Joern Rennecke  <joern.rennecke@embecosm.com>