tile: remove support for TILE64

This chip is no longer being actively developed for (it was superceded
by the TILEPro64 in 2008), and in any case the existing compiler and
toolchain in the community do not support it.  It's unlikely that the
kernel works with TILE64 at this point as the configuration has not been
tested in years.  The support is also awkward as it requires maintaining
a significant number of ifdefs.  So, just remove it altogether.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

arch/tile/include/asm/elf.h

@@ -30,7 +30,6 @@ typedef unsigned long elf_greg_t;
 #define ELF_NGREG (sizeof(struct pt_regs) / sizeof(elf_greg_t))
 typedef elf_greg_t elf_gregset_t[ELF_NGREG];
 
-#define EM_TILE64  187
 #define EM_TILEPRO 188
 #define EM_TILEGX  191