ALSA: hda - Select INPUT for Realtek HD-audio codec

The commit commit [33f4acd3: ALSA: hda - Enable mic mute hotkey
and LEDs for an HP machine] introduced a quirk for a HP machine
involving with the input event handling.  Although the relevant code
is protected via IS_ENABLED(CONFIG_INPUT), this doesn't suffice when
the audio driver is built in while the input is module.

As an easy workaround, this patch forcibly selects CONFIG_INPUT in
Kconfig.  This shouldn't be a practical problem since CONFIG_INPUT is
almost mandatory for all systems.  Also, this allows to remove the
ugly ifdefs in the code.

Fixes: 33f4acd3 ('ALSA: hda - Enable mic mute hotkey and LEDs for an HP machine')
Acked-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/Kconfig

@@ -107,6 +107,7 @@ config SND_HDA_PATCH_LOADER
 config SND_HDA_CODEC_REALTEK
 	tristate "Build Realtek HD-audio codec support"
 	select SND_HDA_GENERIC
+	select INPUT
 	help
 	  Say Y or M here to include Realtek HD-audio codec support in
 	  snd-hda-intel driver, such as ALC880.

sound/pci/hda/patch_realtek.c

@@ -121,9 +121,7 @@ struct alc_spec {
 	hda_nid_t pll_nid;
 	unsigned int pll_coef_idx, pll_coef_bit;
 	unsigned int coef0;
-#if IS_ENABLED(CONFIG_INPUT)
 	struct input_dev *kb_dev;
-#endif
 };
 
 /*
@@ -3476,7 +3474,6 @@ static void alc280_fixup_hp_gpio4(struct hda_codec *codec,
 	}
 }
 
-#if IS_ENABLED(CONFIG_INPUT)
 static void gpio2_mic_hotkey_event(struct hda_codec *codec,
 				   struct hda_jack_callback *event)
 {
@@ -3489,12 +3486,10 @@ static void gpio2_mic_hotkey_event(struct hda_codec *codec,
 	input_report_key(spec->kb_dev, KEY_MICMUTE, 0);
 	input_sync(spec->kb_dev);
 }
-#endif
 
 static void alc280_fixup_hp_gpio2_mic_hotkey(struct hda_codec *codec,
 					     const struct hda_fixup *fix, int action)
 {
-#if IS_ENABLED(CONFIG_INPUT)
 	/* GPIO1 = set according to SKU external amp
 	   GPIO2 = mic mute hotkey
 	   GPIO3 = mute LED
@@ -3550,7 +3545,6 @@ static void alc280_fixup_hp_gpio2_mic_hotkey(struct hda_codec *codec,
 		input_unregister_device(spec->kb_dev);
 		spec->kb_dev = NULL;
 	}
-#endif
 }
 
 static void alc269_fixup_hp_line1_mic1_led(struct hda_codec *codec,