The test here is intended intended to prevent shift wrapping bugs when
we do "1U << idx2".  We should consider the number of bits in a u32
instead of the number of bytes.

[fix another chunk similarly by tiwai]

Fixes: 7bb2491b ('ALSA: Add kconfig to specify the max card numbers')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>