driver-hidpp10: fill the number of buttons from the first profile
driver-hidpp10: fill the number of buttons from the first profile

We don't know the HID++ 1.0 request to check for the number of buttons or
profiles, this is the next-best thing.

Signed-off-by: Peter Hutterer <b9c50af7afa7642f6f854434cda9ffe54ece8b85@who-t.net>

whot/libratbag-old,NoXPhasma/libratbag,NoXPhasma/libratbag,NoXPhasma/libratbag,whot/libratbag,bentiss/libratbag-old,libratbag/libratbag,whot/libratbag-old,cvuchener/libratbag,cvuchener/libratbag,bentiss/libratbag-old,whot/libratbag,whot/libratbag-old,bentiss/libratbag-old,whot/libratbag,cvuchener/libratbag,libratbag/libratbag,libratbag/libratbag