m32r: remove abort()

Commit 7c2c11b2

 ("arch: define weak abort()") has introduced a weak
abort() which is common for all arch.  And, so we will not need arch
specific abort which has the same code as the weak abort().  Remove the
abort() for m32r.

Link: http://lkml.kernel.org/r/1516912339-5665-1-git-send-email-sudipm.mukherjee@gmail.com
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>