tgsi: add option to dump floats as hex values

tgsi: add option to dump floats as hex values

This adds support to the parser to accept hex values as floats,
and then adds support to the dumper to allow the user to select
to dump float as 32-bit hex numbers.

This is required to get accurate values for virgl use of TGSI.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>