drm/i915/display: remove unused intel-mid.h include

Nothing from intel-mid.h and this is only available on x86, so remove it
as we prepare support for other architectures.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211007233212.3896460-4-lucas.demarchi@intel.com

drivers/gpu/drm/i915/display/intel_dsi_vbt.c

@@ -31,7 +31,6 @@
 #include <linux/pinctrl/machine.h>
 #include <linux/slab.h>
 
-#include <asm/intel-mid.h>
 #include <asm/unaligned.h>
 
 #include <drm/drm_crtc.h>