we don't need arm neon header for inline asm
Revert "remove 16-bit renderer"

This reverts commit 212f428bb7ebfee0ae2f7e18edd562c3eb42419a.

Conflicts:
	src/gles/ztriangle.c
add TGL_PIXEL_TYPE to clean up conversions
combine smooth render paths for 16 and 32-bit