lk2nd 21.0

- Updated debugging tools for SPMI regulators
- LK2ND_FASTBOOT_DELAY= build flag is added
- Continue option added to the menu screen
- Menu navigation hints are now customizeable
- GPIO leds on devices can be configured on boot
- Various improvements to extlinux.conf support
- Various other fixes and improvements

New devices:
- Motorola Moto G6 Play (XT1922-X, jeter)
- Huawei Nova (cannes)
- Huawei Maimang 4
- BlackBerry Passport
- Xiaomi Mi Max (hydrogen)
- Xiaomi Mi Max 2 (oxygen)
- Xiaomi Redmi 4 (prada)
- Motorola Moto E5 Plus
- Xiaomi Redmi 7A
- XiaoXun JZ0145 v33
- Motorola Moto E5 (nora)
- amsung Galaxy Ace 3 LTE
- Samsung Galaxy Express
- Huawei MediaPad T2 10.0 Pro (federer)
- Haier G151
- Sony Xperia M4 Aqua
- LG G5 (H850)
- Samsung Galaxy Tab A (2018) (SM-T595)
- Huawei Nexus 6P (Angler)
- Wiko Pulp 4G
- Samsung Galaxy Express (GT-I8730)
- Samsung Galaxy E7 LTE (E700F)
- ZTE Axon 7
- Samsung Galaxy Note 3 (T-Mobile US) (SM-N900T)
- Samsung Galaxy S5 (T-Mobile US) (SM-G900T)
- Samsung Galaxy J5 2016 U+ (SM-J510L)
- Lenovo yoga tablet 10 WIFI
- Xiaomi Mi 5s
- Xiaomi Mi 5s Plus
- Samsung Galaxy Tab 2 10.1 (SGH-I497)
- Alcatel Idol 4 (idol4)
- Lenovo Tab 10 (TB-X103F)
- Motorola Moto G4 / G4Plus (athene)
- EE Harrier Mini
- Lenovo Yoga Tab 3 8
- Sony Xperia M2 (eagle)
- Redmi GO
- Redmi 5A
- Vivo Y31 (2015)
- Lenovo Tab M10 HD
- Sony Xperia SP (huashan)
- Panasonic ELUGA U2
- Fossil Gen 6 (hoki)