mm/debug_vm_pgtable: use struct pgtable_debug_args in basic tests

This uses struct pgtable_debug_args in the basic test functions.  The
unused variables @pgd_aligned and @p4d_aligned in debug_vm_pgtable() are
dropped.

Link: https://lkml.kernel.org/r/20210809092631.1888748-3-gshan@redhat.com
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu>	[powerpc 8xx]
Tested-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>	[s390]
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chunyu Hu <chuhu@redhat.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>