x86/crash: Fix minor typo/bug in debug message

The pr_debug() intends to display the memsz member, but the
parameter is actually the bufsz member (which is already
displayed). Correct this to display memsz value.

Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Baoquan He <bhe@redhat.com>
Link: https://lore.kernel.org/r/20220413164237.20845-2-eric.devolder@oracle.com