pinctrl: intel: Update description in struct intel_community

It appears that most of the drivers, that are using struct intel_community,
utilize gpps rather than gpp_size. Update comment accordingly.

While here, correct the description of gpp_size, i.e. remove double space
and drop redundant 'etc.' part.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>