Add support for rear 'STEALTH' leds on 14K1EMS1.108 (Stealth 14 Studio A13V)

[bluer222]

Adds support for the leds on the rear of MSI stealth laptops for 14K1EMS1.108 (Stealth 14 Studio A13V)

Changes:

• add stealth_led_address and stealth_led_bit (as it uses a different bit than the existing keyboard leds)
• add logic for handling stealth led (exactly the same as mic and micmute leds)
• create CONF_G2_11, a direct copy of CONF_G2_5
• set 14K1EMS1.108 to use the new CONF_G2_11
• set stealth_led_address = 0x2c and stealth_led_bit = 4 in CONF_G2_11

Testing:

• windows method used to find address and value for toggling the led
• Verified with RWEverything and msi-ec debug: writing 0x2c = 0x10 turns on the stealth LED; 0x2c = 0x12 turns on stealth+micmute; 0x2c = 0x00 turns both off.
• Built and loaded the kernel module with these changes; toggling /sys/class/leds/platform::stealth/brightness between 1 and 0 turns the rear light on and off without any other effects.

Note:

• setting /sys/devices/platform/msi-ec/shift_mode to eco turns off the stealth led regardless of the value set in /sys/class/leds/platform::stealth/brightness, this is the same behavior as using the official MSI Center app