Update lv_conf.defaults

[liamHowatt]

• enable evdev
• Use CLIB stdlib
• Put OS and sysmon in the file, even though not set, as a cue to the user they may want to enable them
• double-buffered partial fbdev
• high res demo and LV_FONT_FMT_TXT_LARGE
• matrix, float, lottie moved down
• use lv_conf.h as a dependency in the Makefile so make detects changes to lv_conf.h

[kisvegabor]

Suggested change

	# LV_USE_OS LV_OS_PTHREAD
	# LV_DRAW_SW_DRAW_UNIT_CNT 2
	LV_USE_OS LV_OS_PTHREAD
	LV_DRAW_SW_DRAW_UNIT_CNT 1

Please test this with our medical demo. It might work better. If really so, let's use it as default.

[liamHowatt]

I tried and and it has the slowness issue with 1 draw unit.

[liamHowatt]

I remembered just now that the color depth should be 16 as discussed. I hope it won't cause 32 bit display users to suffer a regression.

Also updated the submodule.

[kisvegabor]

Great, thank you!