[binutils][arm] Arm CDE CX*A instructions allow condition code

The implementation of the Arm CDE CX*A instructions doesn't allow a
condition code on the instructions but does allow the instruction in an
ITBlock.

The specification has been recently updated, though this is yet to be
published.

The instructions now should allow a suffix, and should behave in the
standard way around ITBlocks.

This patch removes the custom pred_instruction_type and handling for
these instructions, and uses the standard INSIDE_IT_INSN predication
type to describe the new instructions.

gas/ChangeLog:

2020-02-26  Matthew Malcomson  <matthew.malcomson@arm.com>

	* config/tc-arm.c (enum pred_instruction_type): Remove
	NEUTRAL_IT_NO_VPT_INSN predication type.
	(cxn_handle_predication): Modify to require condition suffixes.
	(handle_pred_state): Remove NEUTRAL_IT_NO_VPT_INSN cases.
	* testsuite/gas/arm/cde-scalar.s: Update test.
	* testsuite/gas/arm/cde-warnings.l: Update test.
	* testsuite/gas/arm/cde-warnings.s: Update test.