Add GC9A01 Driver (#452)

* Added driver for gc9a01 round display and example code

examples/gc9a01/main.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"machine"
+	"time"
+
+	"image/color"
+
+	"tinygo.org/x/drivers/gc9a01"
+)
+
+func main() {
+	machine.SPI0.Configure(machine.SPIConfig{
+		Frequency: 80000000,
+	})
+	display := gc9a01.New(machine.SPI0, machine.P6, machine.P7, machine.P8, machine.P9)
+	display.Configure(gc9a01.Config{Orientation: gc9a01.HORIZONTAL, Width: 240, Height: 240})
+
+	width, height := display.Size()
+
+	white := color.RGBA{255, 255, 255, 255}
+	red := color.RGBA{255, 0, 0, 255}
+	blue := color.RGBA{0, 0, 255, 255}
+	green := color.RGBA{0, 255, 0, 255}
+	black := color.RGBA{0, 0, 0, 255}
+
+	display.FillScreen(black)
+
+	display.FillRectangle(0, 0, width/2, height/2, white)
+	display.FillRectangle(width/2, 0, width/2, height/2, red)
+	display.FillRectangle(0, height/2, width/2, height/2, green)
+	display.FillRectangle(width/2, height/2, width/2, height/2, blue)
+	display.FillRectangle(width/4, height/4, width/2, height/2, black)
+
+	for {
+		time.Sleep(time.Hour)
+	}
+
+}