drm/amdgpu: drop alpha support

			return -EINVAL;

		mem->bus.base = adev->mc.aper_base;

		mem->bus.is_iomem = true;

#ifdef __alpha__

		/*

		 * Alpha: use bus.addr to hold the ioremap() return,

		 * so we can modify bus.base below.

		 */

		if (mem->placement & TTM_PL_FLAG_WC)

			mem->bus.addr =

				ioremap_wc(mem->bus.base + mem->bus.offset,

					   mem->bus.size);

		else

			mem->bus.addr =

				ioremap_nocache(mem->bus.base + mem->bus.offset,

						mem->bus.size);

		if (!mem->bus.addr)

			return -ENOMEM;

		/*

		 * Alpha: Use just the bus offset plus

		 * the hose/domain memory base for bus.base.

		 * It then can be used to build PTEs for VRAM

		 * access, as done in ttm_bo_vm_fault().

		 */

		mem->bus.base = (mem->bus.base & 0x0ffffffffUL) +

			adev->ddev->hose->dense_mem_base;

#endif

		break;

	default:

		return -EINVAL;