hwdb: Fix Pinebook Pro's brightness up/down and sleep keys

hwdb: Fix Pinebook Pro's brightness up/down and sleep keys

Pinebook Pro's display brightness up & down keys do not work until the
keys are mapped to the corresponding codes.

Also, the sleep key is mapped to KEY_POWER code originally. This quirk
maps the sleep key to the KEY_SLEEP code.

This idea comes from the pinebookpro-post-install package [1] of Manjaro
ARM, which is the preloaded OS on Pinebook Pro.

[1]: https://gitlab.manjaro.org/manjaro-arm/packages/community/pinebookpro-post-install/-/commit/7ab1a134ea9d5b55d99de567d1ebee4ebd6f6640