fastuidraw/utils: add bound checks to pack_bits and unpack_bits
fastuidraw/utils: add bound checks to pack_bits and unpack_bits

Add bound checks, in the form of FASTUIDRAWassert() to pack_bits(),
uint64_pack_bits(), unpack_bits() and uint64_unpack_bits() guarding
against trying to use too many bits and overflow.

01org/fastuidraw,01org/fastuidraw