intel/compiler: Change src1 reg type to unsigned doubleword

intel/compiler: Change src1 reg type to unsigned doubleword

To have uniform behavior while disassembling send(c) instruction use
register type of unsigned doubleword for src1 when message descriptor is
immediate value. Bspec does not specifiy anything for src1 immediate
default type.

Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Sagar Ghuge <sagar.ghuge@intel.com>