Adds fixed pin information

[rubienr]

This PR declares binary information of several I/O Pins:

• LEDs
• RGB LED
• buzzer
• TFT SPI pins
• touch I2C pins
• buttons
• joystick (analogue in)

PR relates to

• Missing pins in the README.md Pinout section #2
• and adds missing info about pins 4: TFT (MISO) , 10: RST, Touch and 11: INT, Touch.

The information can be simply recalled by picotool as follows:

picotool info -a foo.elf
File foo.elf:

Program Information
 name:          foo
 version:       0.1
...
 features:      TFT 480x320 (SPI0)
                Capacitive Touch (I2C0)
                Joystick 2-axis (ADC0, ADC1)
                RGB LED 1x (WS2012, PIO0)
                UART stdin / stdout
...
Fixed Pin Information
 0:   UART0 TX
 1:   UART0 RX
 2:   SPI0 SCK, TFT (SCLK)
 3:   SPI0 TX, TFT (MOSI)
 4:   TFT (MISO)
 5:   SPI0 CSn, TFT (CS)
 6:   TFT (DC)
 7:   TFT (RST)
 8:   I2C0 SDA, Touch
 9:   I2C0 SCL, Touch
 10:  RST, Touch
 11:  INT, Touch
 12:  PIO0, RGB LED
 26:  X-axis (ADC0)
 27:  Y-axis (ADC1)
...