drm/komeda: Build komeda to be a platform module

Implement a simple wrapper for platform module to build komeda to module,
Also add a very simple D71 layer code to show how to discover a product.
Komeda driver direct bind the product ENTRY function xxx_identity to DT
compatible name like:

d71_product = {
	.product_id = MALIDP_D71_PRODUCT_ID,
	.identify = d71_identify,
},

const struct of_device_id komeda_of_match[] = {
	{ .compatible = "arm,mali-d71", .data = &d71_product, },
	{},
};

Then when linux found a matched DT node and call driver to probe, we can
easily get the of data, and call into the product to do the identify:

komeda_bind()
{
    ...
    product = of_device_get_match_data(dev);

    product->identify();
    ...
}

Changes in v4:
- Replaced kzalloc with devm_kzalloc

Changes in v3:
- Fixed style problem found by checkpatch.pl --strict.

Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>