tty/vt: consolemap: zero uni_pgdir using kcalloc()

The newly allocated p->uni_pgdir[n] is initialized to NULLs right after
a kmalloc_array() allocation. Combine these two using kcalloc().

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220607104946.18710-11-jslaby@suse.cz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>