[AArch64] Add more unpredicated MOVPRFX alternatives

[AArch64] Add more unpredicated MOVPRFX alternatives

FABD and some immediate instructions were missing MOVPRFX alternatives.
This is tested by the ACLE patches but is really an independent improvement.

2019-08-15  Richard Sandiford  <richard.sandiford@arm.com>
	    Kugan Vivekanandarajah  <kugan.vivekanandarajah@linaro.org>

gcc/
	* config/aarch64/aarch64-sve.md (add<SVE_I:mode>3, sub<SVE_I:mode>3)
	(<LOGICAL:optab><SVE_I:mode>3, *add<SVE_F:mode>3, *mul<SVE_F:mode>3)
	(*fabd<SVE_F:mode>3): Add more MOVPRFX alternatives.

Co-Authored-By: Kugan Vivekanandarajah <kuganv@linaro.org>
From-SVN: r274513