selftests/mm: fix validate_addr() helper

validate_addr() checks whether the address returned by mmap() lies in the
low or high VA space, according to whether a high addr hint was passed or
not.  The fix commit mentioned below changed the code in such a way that
this function will always return failure when passed high_addr == 1; addr
will be >= HIGH_ADDR_MARK always, we will fall down to "if (addr >
HIGH_ADDR_MARK)" and return failure.  Fix this.

Link: https://lkml.kernel.org/r/20250620111150.50344-1-dev.jain@arm.com


Fixes: d1d86ce2 ("selftests/mm: virtual_address_range: conform to TAP format output")
Signed-off-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>