linux (NXP iMX8): add missing include for dp-hmdi for 6.3

Needs to be reviewed further with:
- f9bfd326f5
- v1 https://lore.kernel.org/linux-arm-kernel/cover.1590982881.git.Sandor.yu@nxp.com/
- v2 https://lore.kernel.org/linux-arm-kernel/cover.1667463263.git.Sandor.yu@nxp.com/
- v3 https://lore.kernel.org/linux-arm-kernel/cover.1667911321.git.Sandor.yu@nxp.com/
- v4 https://lore.kernel.org/linux-arm-kernel/cover.1669013346.git.Sandor.yu@nxp.com/
- v5 https://lore.kernel.org/linux-arm-kernel/cover.1669620155.git.Sandor.yu@nxp.com/

https://elixir.bootlin.com/linux/v6.1.25/A/ident/drm_encoder_helper_add
https://github.com/nxp-imx/linux-imx/tree/lf-6.1.y/drivers/gpu/drm/imx/mhdp

read at https://github.com/LibreELEC/LibreELEC.tv/pull/

xxx5269

projects/NXP/devices/iMX8/patches/linux/0060-mhdp-dp-hdmi-add-missing-include-patch-for-6-3.patch

@@ -0,0 +1,10 @@
+--- a/drivers/gpu/drm/imx/mhdp/cdns-mhdp-imxdrv.c	2023-04-24 10:04:54.095068512 +0000
++++ b/drivers/gpu/drm/imx/mhdp/cdns-mhdp-imxdrv.c	2023-04-25 13:35:44.405261313 +0000
+@@ -12,6 +12,7 @@
+ #include <drm/drm_vblank.h>
+ #include <drm/drm_crtc_helper.h>
+ #include <drm/drm_encoder_slave.h>
++#include <drm/drm_modeset_helper_vtables.h>
+ 
+ #include <uapi/linux/media-bus-format.h>
+