Remove the enter/leave macros and the corresponding calls.
These are obsolete since ftrace is available.

Co-developed-by: Lukas Panzer <lukas.panzer@fau.de>
Signed-off-by: Lukas Panzer <lukas.panzer@fau.de>
Signed-off-by: Simon Geis <simon.geis@fau.de>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>