Unhook drm_encoder_slave.c until rewritten with NetBSD i2c.
Use only C99-style initializers in DRM_MODE in drm_crtc.h.
Move OS-independent cruft from drm_drv.c to a new drm_fops.c.
Define spin_is_locked in <linux/spinlock.h>.
Define list_first_entry in <linux/list.h>.
Add variants of drm wait/wakeup for spin locks in drm_wait_netbsd.h.
Name fp->f_data in drm_close for clarity.
Tag the XXX's in drm_drv.c for enhanced greppability.
Fix up drm_read and drm_poll a little.

Still #ifdef'd out because it needs some selnotify calls to actually
work, but the #ifdef'd code now compiles and looks more plausible --
doesn't hold onto spin locks during loops and uiomoves.
Move WARN and WARN_ON to <asm/bug.h> and add BUG_ON.
drm_crtc.c needs <asm/bug.h>.
drm_crtc_helper.c needs <asm/bug.h>.
Convert mutex_init to linux_mutex_init in drm_global.c.
drm_gem.c needs <linux/err.h>, <linux/export.h>, and <asm/bug.h>.
Add local drm_memory.c to implement drm_ioremap and drm_iounmap.
drm_global.c needs <linux/kernel.h>, <linux/export.h>, and <asm/bug.h>.
In drm_global_release, declare item ignored.
Avoid INT_MAX in PTR_ERR; check for truncation instead.
Implement hash_long in <linux/hash.h>.

Uses the same hash function as in Linux, implemented differently.
Implement unlikely as __predict_false in <linux/kernel.h>.