protocol: Add fp16 formats

Add 64 bpp 16:16:16:16 half float pixel formats. Each 16 bit component is
formatted in IEEE-754 half-precision float (binary16) 1:5:10
MSb-sign:exponent:fraction form.

Mesa uses WL_SHM_FORMAT_* for swrast path.

Signed-off-by: Kevin Strasser <kevin.strasser@intel.com>
1 job for fp16 in 1 minute and 37 seconds
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passed #212418
build-native

00:01:37