Add Pimoroni HDMI Demo board serialiser config

This change adds support to our upcoming HDMI demo board for Pico, would you mind including the definition for it in the main repo please?

software/include/common_dvi_pin_configs.h

@@ -65,4 +65,14 @@ static const struct dvi_serialiser_cfg pico_sock_cfg = {
 	.invert_diffpairs = false
 };
 
+// The HDMI socket on Pimoroni Pico Demo HDMI
+// (we would talk about rev B if we had a rev B...)
+static const struct dvi_serialiser_cfg pimoroni_demo_hdmi_cfg = {
+	.pio = pio0,
+	.sm_tmds = {0, 1, 2},
+	.pins_tmds = {8, 10, 12},
+	.pins_clk = 6,
+	.invert_diffpairs = true
+};
+
 #endif