ARC: export __udivdi3 for modules

Some module using div_u64() was failing to link because the libgcc 64-bit
divide assist routine was not being exported for modules

Reported-by:  <avinashp@quantenna.com>
Cc: stable@vger.kernel.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>