Change the ARM assembler's ADR and ADRl pseudo-ops so that they will only set the...

Change the ARM assembler's ADR and ADRl pseudo-ops so that they will only set the bottom bit of imported thumb function symbols if the -mthumb-interwork option is active.

For more information see the email thread starting here:
https://www.sourceware.org/ml/binutils/2018-05/msg00348.html

	PR 21458
	* tc-arm.c (do_adr): Only set the bottom bit of an imported thumb
	function symbol address if -mthumb-interwork is active.
	(do_adrl): Likewise.
	* doc/c-arm.texi: Update descriptions of the -mthumb-interwork
	option and the ADR and ADRL pseudo-ops.
	* NEWS: Mention the new behaviour of the ADR and ADRL pseudo-ops.
	* testsuite/gas/arm/pr21458.d: Add -mthumb-interwork option to
	assembler command line.
	* testsuite/gas/arm/adr.d: Likewise.
	* testsuite/gas/arm/adrl.d: Likewise.