device/*-asus-grouper: upgrade to 5.6_rc2

CONFIG options added:
- nvidia tegra partition support (now it's kernel option)
- CONFIG_SECCOMP support (needed for Epiphany and lot of others)
- CONFIG_USER_NS required for bubble wrap (used by Epiphany)

DTS change:
- grouper we all have has codename "tilapia" (w/ GSM), since no-one had "older" grouper
- in future, when we get testing, we'll add "real" grouper (wo/ GSM)
- no functional change in DTS (except wiring SMB347 driver)

Kernel changes:
- added SMB347 driver support (now it's able report charging state)

v2: fixed missing SMB347 in config_armv7