selftests/mm: skip test for non-LPA2 and non-LVA systems

Post my improvement of the test in e4a4ba41 ("selftests/mm:
va_high_addr_switch: dynamically initialize testcases to enable LPA2
testing"):

The test begins to fail on 4k and 16k pages, on non-LPA2 systems.  To
reduce noise in the CI systems, let us skip the test when higher address
space is not implemented.

Link: https://lkml.kernel.org/r/20240718052504.356517-1-dev.jain@arm.com


Fixes: e4a4ba41 ("selftests/mm: va_high_addr_switch: dynamically initialize testcases to enable LPA2 testing")
Signed-off-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>