Update to kernel headers v5.4 + Morello
Regenerate the headers from linux-stable v5.4.50, with the Morello patches from [1] applied on top.
Also manually update scsi.h, as it got modified since v5.0 by [2].
[1] https://git.morello-project.org/morello/kernel/morello-ack/-/tree/morello/release-1.0 [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=59abc8cc0585
Change-Id: Ib99e4d0f69b47dec1b34d19466e14f640d695c96