xtensa: add missing atomic intrinsics
xtensa: add missing atomic intrinsics

Add more atomic intrinsics. These are mostly non 32-bit versions, which
are not support by Xtensa. This file needs some more clean-up and
consolidation.

Signed-off-by: Chris Zankel <711c73f64afdce07b7e38039a96d2224209e9a6c@zankel.net>

waweber/uclibc-clang,hjl-tools/uClibc,ffainelli/uClibc,kraj/uClibc,kraj/uclibc-ng,foss-for-synopsys-dwc-arc-processors/uClibc,majek/uclibc-vx32,groundwater/uClibc,foss-for-synopsys-dwc-arc-processors/uClibc,brgl/uclibc-ng,hwoarang/uClibc,kraj/uclibc-ng,wbx-github/uclibc-ng,groundwater/uClibc,ddcc/klee-uclibc-0.9.33.2,hwoarang/uClibc,foss-xtensa/uClibc,ddcc/klee-uclibc-0.9.33.2,ffainelli/uClibc,ddcc/klee-uclibc-0.9.33.2,groundwater/uClibc,mephi42/uClibc,wbx-github/uclibc-ng,ffainelli/uClibc,kraj/uclibc-ng,hwoarang/uClibc,foss-xtensa/uClibc,kraj/uclibc-ng,foss-for-synopsys-dwc-arc-processors/uClibc,brgl/uclibc-ng,kraj/uClibc,mephi42/uClibc,brgl/uclibc-ng,ffainelli/uClibc,wbx-github/uclibc-ng,ffainelli/uClibc,kraj/uClibc,majek/uclibc-vx32,kraj/uClibc,groundwater/uClibc,majek/uclibc-vx32,waweber/uclibc-clang,majek/uclibc-vx32,hwoarang/uClibc,foss-xtensa/uClibc,mephi42/uClibc,ddcc/klee-uclibc-0.9.33.2,hjl-tools/uClibc,hjl-tools/uClibc,waweber/uclibc-clang,hjl-tools/uClibc,hjl-tools/uClibc,wbx-github/uclibc-ng,groundwater/uClibc,waweber/uclibc-clang,foss-for-synopsys-dwc-arc-processors/uClibc,foss-xtensa/uClibc,mephi42/uClibc,brgl/uclibc-ng