radv: fix possible stack corruption

drmGetDevices2 takes count and not size. Probably hasn't caused problems
yet in practice and was missed as setups with more than 8 DRM devices
are not very common.

Fixes: 743315f2 "radv: do not open random render node(s)"
Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

src/amd/vulkan/radv_device.c

@@ -401,7 +401,7 @@ radv_enumerate_devices(struct radv_instance *instance)
 
 	instance->physicalDeviceCount = 0;
 
-	max_devices = drmGetDevices2(0, devices, sizeof(devices));
+	max_devices = drmGetDevices2(0, devices, ARRAY_SIZE(devices));
 	if (max_devices < 1)
 		return VK_ERROR_INCOMPATIBLE_DRIVER;