ALSA: seq: Fix snd_seq_call_port_info_ioctl in compat mode

ALSA: seq: Fix snd_seq_call_port_info_ioctl in compat mode

This reverts one hunk of
commit 2a8fd2ea22be ("ALSA: sound/core: use memdup_user()"), which
replaced a number of kmalloc followed by memcpy with memdup calls.

In this case, we are copying from a struct snd_seq_port_info32 to a
struct snd_seq_port_info, but the latter is 4 bytes longer than the
32-bit version, so we need to separate kmalloc and copy calls.

Fixes: 2a8fd2ea22be ('ALSA: sound/core: use memdup_user()')
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>