xtensa: align data naturally when optimizing for size

xtensa: align data naturally when optimizing for size

gcc for xtensa always aligns data at least to a word boundary, even when
it has smaller natural alignment. This results in unexpectedly high data
section sizes and unreasonable amount of wasted space when linking
objects compiled with -fdata-sections flag.

Align data naturally when optimization for size is enabled.

2015-02-22  Max Filippov  <jcmvbkbc@gmail.com>

gcc/
	* config/xtensa/xtensa.h (CONSTANT_ALIGNMENT, DATA_ALIGNMENT):
	use natural alignment when optimizing for size.

From-SVN: r220923