m32r: fix build failure

The allmodconfig build of m32r is failing with the error:

  lib/mpi/mpih-div.o: In function 'mpihelp_divrem':
  mpih-div.c:(.text+0x40): undefined reference to 'abort'
  mpih-div.c:(.text+0x40): relocation truncated to fit:
	R_M32R_26_PCREL_RELA against undefined symbol 'abort'

The function 'abort' was never defined for the m32r architecture.

Create 'abort' as is done in other arch like 'arm' and 'unicore32'.

Link: http://lkml.kernel.org/r/1506727220-6108-1-git-send-email-sudip.mukherjee@codethink.co.uk
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/m32r/kernel/traps.c

@@ -114,6 +114,15 @@ static void set_eit_vector_entries(void)
 	_flush_cache_copyback_all();
 }
 
+void abort(void)
+{
+	BUG();
+
+	/* if that doesn't kill us, halt */
+	panic("Oops failed to kill thread");
+}
+EXPORT_SYMBOL(abort);
+
 void __init trap_init(void)
 {
 	set_eit_vector_entries();