lttng-modules: backport patches to fix build against 5.12+ kernel

Add the following patches from stable-2.12 branch of lttng repository
to fix errors when building lttng-modules against 5.12+ kernel
since they are not present on the release 2.12.5:

- 17cd2dc9 fix: block: add a disk_uevent helper (v5.12)
- 127135b6 fix backport: block: add a disk_uevent helper (v5.12)
- 853d5903 fix: mm, tracing: kfree event name mismatching with
provider kmem (v5.12)

Signed-off-by: Vinicius Aquino <vinicius.aquino@ossystems.com.br>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>