[PATCH V3 0/5] selftests/powerpc: Add NX-GZIP engine testcase

[Raphael Moreira Zinsly]

This patch series are intended to test the POWER9 Nest
Accelerator (NX) GZIP engine that is being introduced by
https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-March/205659.html
More information about how to access the NX can be found in that patch, also a
complete userspace library and more documentation can be found at:
https://github.com/libnxz/power-gzip

Changes in V3:
	- Defined a macro and increased the number of retries for page faults
	  to work in system with less memory, mentioning the issue on README.
	- Returned to use volatile on the touch pages routine and a few structs
	  on inc/nxu.h as they are handled by hardware and some compilers could
	  optmize it wrongly.
	- Moved common functions to gzip_vas.c.