The some indices of capture elements of AD1988 are wrongly assigned.
This patch fixes it.  See ALSA bug#3795
	https://bugtrack.alsa-project.org/alsa-bug/view.php?id=3795
Signed-off-by: Takashi Iwai <tiwai@suse.de>
 static struct hda_input_mux ad1988_6stack_capture_source = {
        .num_items = 5,
        .items = {
-               { "Front Mic", 0x0 },
-               { "Line", 0x1 },
-               { "Mic", 0x4 },
+               { "Front Mic", 0x1 },   /* port-B */
+               { "Line", 0x2 },        /* port-C */
+               { "Mic", 0x4 },         /* port-E */
                { "CD", 0x5 },
                { "Mix", 0x9 },
        },
 static struct hda_input_mux ad1988_laptop_capture_source = {
        .num_items = 3,
        .items = {
-               { "Mic/Line", 0x0 },
+               { "Mic/Line", 0x1 },    /* port-B */
                { "CD", 0x5 },
                { "Mix", 0x9 },
        },