arm: remove fslsdma from GENERIC
The fslsdma device requires sdma_fw, but that's not included in
GENERIC. That firmware is not in the FreeBSD tree at the moment, but
could easily be.
The license for the firmware can be found in the linux firmware repo:
https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/commit/?id=3123d78e09d2f815de4d94aa35c07b3c0469c80e
and looks to be a BSD license + no reverse engineer.
We can add this back after the firmware is imported, made a port, or
whose automatic loading can be made to happen.
Reviewed by: imp (with ian finding the license)
PR: 237466
MFC after: 1 week
(cherry picked from commit 9e3761d126c5c019d6c935e83989928eb1a0e76e)