LinuxKPI: sort dev_<loglevel>() functions

Sort the dev_<loglevel> functions by loglevel order, add the dev_alert()
version and an indentation change.

No functional changes.

Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D43719

(cherry picked from commit 70617458676eb0b0076aa19657d21f2a9f3b704a)