The new Dell laptop with codec 256 can't detect headset mic when
headset was inserted on the machine. From alsa-info, we check
init_pin_configs and need to define the new register value for pin
0x1d & 0x1e because the original macro ALC256_STANDARD_PINS can't
match pin definition. Also, the macro ALC256_STANDARD_PINS is
simplified by removing them. This makes headset mic works on laptop.

Codec: Realtek ALC256
Vendor Id: 0x10ec0256
Subsystem Id: 0x102806f2

BugLink: https://bugs.launchpad.net/bugs/1478497Signed-off-by: NWoodrow Shen <woodrow.shen@canonical.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>