Use SCALAR_INT_TYPE_MODE in loc_list_from_tree_1

Use SCALAR_INT_TYPE_MODE in loc_list_from_tree_1

This follows on from similar changes a couple of months ago and
is needed when general modes have variable size.

2017-10-23  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* dwarf2out.c (loc_list_from_tree_1): Use SCALAR_INT_TYPE_MODE

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r254001