ext4: Convert mballoc cr (criteria) to enum

ext4: Convert mballoc cr (criteria) to enum

Convert criteria to be an enum so it easier to maintain and
update the tracefiles to use enum names. This change also makes
it easier to insert new criterias in the future.

There is no functional change in this patch.

Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/5d82fd467bdf70ea45bdaef810af3b146013946c.1685449706.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>