[mips] Fix ambiguous .md attribute uses

[mips] Fix ambiguous .md attribute uses

This patch is part of a series that fixes ambiguous attribute
uses in .md files, i.e. cases in which attributes didn't use
<ITER:ATTR> to specify an iterator, and in which <ATTR> could
have different values depending on the iterator chosen.

No behavioural change -- produces the same code as before.

2019-07-16  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* config/mips/micromips.md (*movep<MOVEP1:mode><MOVEP2:mode>):
	Explicitly use <MOVEP1:MODE> for the mode attribute.

From-SVN: r273508