Add support for Pirate Audio ST7789 HAT

[ricmatsui]

Closes #199. The Pirate Audio collection of pHATs use GPIO 9 as the Data/Control pin:

https://pinout.xyz/pinout/pirate_audio_3w_amp
https://pinout.xyz/pinout/pirate_audio_headphone_amp
https://pinout.xyz/pinout/pirate_audio_line_out
https://pinout.xyz/pinout/pirate_audio_speaker

Currently GPIO 9 is always set as MISO which causes the display to not receive any commands. This PR adds a check to only set the pin as MISO if it is not the Data/Control pin, and adds a PIRATE_AUDIO_ST7789_HAT flag to configure the pins.

Tested on a Pi Zero W with -DPIRATE_AUDIO_ST7789_HAT=ON -DSPI_BUS_CLOCK_DIVISOR=6 -DBACKLIGHT_CONTROL=ON -DSTATISTICS=1 and ALL_TASKS_SHOULD_DMA disabled:

pirate-audio.mp4

# /boot/config.txt 
display_rotate=1

hdmi_group=2
hdmi_mode=87
hdmi_cvt=240 240 60 1 0 0 0
hdmi_force_hotplug=1

[juj]

Great work!

[antiero]

@ricmatsui - amazing thanks. What demo are you running, looks cool!

[ricmatsui]

Thanks @antiero! The demo is the Pi VideoCore Hello Teapot sample that was mentioned in #187