devfs: translate partition offsets in B_TRIM_DEVICE

Fixes bfs part of #10336. Untested on SATA (don't have a testing drive
to sacrifice) but working fine on SD/MMC.

This requires moving the copy from kernel to userland into the devfs. As
a result the code in the disk drivers becomes a bit simpler.

Also add some documentation for the common ioctls to implement for a
disk device.

Change-Id: Ie84b6a1d293828d33902a64b3c9d4b19aa6eacb1
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3640
Reviewed-by: Jérôme Duval <[email protected]>

headers/os/drivers/Drivers.h

@@ -175,8 +175,8 @@ typedef struct {
 	uint32	range_count;
 	uint64	trimmed_size;			/* filled on return */
 	struct range {
-		uint64	offset;				/* offset (in bytes) */
-		uint64	size;
+		off_t	offset;				/* offset (in bytes) */
+		off_t	size;
 	} ranges[1];
 } fs_trim_data;