platform/x86: hp-wmi: Refactor dock and tablet state fetchers

Both dock and tablet use the HPWMI_HARDWARE_QUERY, but require different
masks. Rather than using two functions with magic masks, define the
masks, and use a common accessor.

Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
Tested-by: Carlo Caione <carlo@endlessm.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>