ARC: export "abort" for modules

BugLink: https://bugs.launchpad.net/bugs/1845405

This is a custom patch (no mainline equivalent) for stable backport only
to address 0-Day kernel test infra ARC 4.x.y builds errors.

The reason for this custom patch as that it is a single patch, touches
only ARC, vs. atleast two 7c2c11b2, dc8635b7 which touch
atleast 3 other arches (one long removed) and could potentially have a
fallout.
Reported-by: kbuild test robot <lkp@intel.com>
CC: stable@vger.kernel.org	# 4.4, 4.9
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

arch/arc/kernel/traps.c

@@ -163,3 +163,4 @@ void abort(void)
 {
 	__asm__ __volatile__("trap_s  5\n");
 }
+EXPORT_SYMBOL(abort);