Firmware: Adjust trackpad for Switch Controller

[arxanas]

Closes #7. This causes the trackpad to only register if you're tapping it (at least, on my Steam Controller). I determined this by uncommenting the debugging statements on these lines:

OpenSteamController/Firmware/OpenSteamController/src/trackpad.c

Lines 1046 to 1054 in 3258015

	/*
	// Debug print to illustrate how difference in adjacent samples
	// can show where finger(s) are on trackpad
	printf("%4d\n", adc_vals_x[0]);
	for (int idx = 0; idx < 11; idx++) {
	printf("%4d\n", adc_vals_x[idx+1] - adc_vals_x[idx]);
	}
	printf("\n");
	*/

Basically, during testing, I observed that the sine wave's amplitude correlates directly with the distance of my finger from the trackpad.

[marxjohnson]

I just tested this out and it's a big improvement, thanks for sharing!

[arxanas]

Builds of:

• Firmware with better touch detection. Note that the D-pad is not bound in this firmware, so the left touchpad doesn't do anything.
• My custom Smash Bros. firmware.

custom-firmwares.zip