Makefile: fix path to compiler
trace: remove unused function
ext4: remove unused variable
Revert "ext4: remove unused variable"

This reverts commit 734241943c531bb533d6c8c230276571f534a58d.
Revert "trace: remove unused function"

This reverts commit 977437971a930d74a43d37dc6bc3e106e51ef077.
mako_hotplug: make max_freq_cap tunable to avoid rebuilding