[ALSA] hda-codec - Fix capture source for Cx5045 codec

For codec conexant 5045, I found that the name of 'Capture Source Items'
is different from the name of mixer.
The mixer is:
HDA_CODEC_VOLUME('Ext Mic Playback Volume', 0x17, 0x2, HDA_INPUT),
HDA_CODEC_MUTE('Ext Mic Playback Switch', 0x17, 0x2, HDA_INPUT),
But the capture source item is :
static struct hda_input_mux cxt5045_capture_source = {
	.num_items = 2,
	.items = {
		{ 'IntMic', 0x1 },
		{ 'LineIn', 0x2 },
	}
};
I think that it's better to change the name of capture_source to avoid
misunderstanding.

Signed-off-by: Jiang zhe <zhe.jiang@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>