omap4_dss

Minimal dummy driver:
```
#include <dm.h>
#include <video.h>

static int omap4_dss_bind(struct udevice *dev)
{
        struct video_uc_plat *uc_plat = dev_get_uclass_plat(dev);

        printf("==============%s===========\n", __func__);

        uc_plat->size = 1024 * 600 * sizeof(u16);
        uc_plat->align = 0x1000;

        printf("%s: size: %x, align: %x\n", __func__, uc_plat->size, uc_plat->align);
        return 0;
}

static const struct udevice_id omap4_dss_ids[] = {
        { .compatible = "ti,omap4-dss" },
        { }
};

U_BOOT_DRIVER(omap4_dss) = {
        .name = "omap4_dss",
        .id = UCLASS_VIDEO,
        .of_match = omap4_dss_ids,
        .bind = omap4_dss_bind,
};
```

and its output on Pandaboard ES:
```
U-Boot SPL 2022.04-rc4-00080-g01f348774f-dirty (Mar 26 2022 - 13:00:49 -0700)
OMAP4460-GP ES1.1
Trying to boot from MMC1
Expected image is not found. Trying to start U-boot


U-Boot 2022.04-rc4-00080-g01f348774f-dirty (Mar 26 2022 - 13:00:49 -0700)

CPU  : OMAP4460-GP ES1.1
Model: TI OMAP4 PandaBoard
Board: OMAP4 Panda
I2C:   ready
DRAM:  ========STARTING VIDEO_RESERVE(40309de4)============
dev: 00000000
Setting addrp to PCI_DEFAULT_FB_SIZE: 0
Video frame buffers from bfff0000 to bfff0000
1 GiB
==============omap4_dss_bind===========
omap4_dss_bind: size: 12c000, align: 1000
Video device 'dss@0' cannot allocate frame buffer memory -ensure the device is set up before relocation
Core:  165 devices, 8 uclasses, devicetree: separate
MMC:   OMAP SD/MMC: 0, OMAP SD/MMC: 1
Loading Environment from FAT... Unable to use mmc 0:1...
Net:   No ethernet found.
Hit any key to stop autoboot:  0
=>
```