drm/i915/dpll: Rename intel_shared_dpll_funcs

Rename intel_shared_dpll_funcs to intel_dpll_funcs
since it needs to represent both shared and individual
dplls.

--v2
-Change intel_global_dpll to intel_dpll_global to be more
in line with the naming standard where the name should
start with the file name [Jani]

--v3
-Drop shared and global altogether [Jani]

--v4
-Keep declarations sorted [Jani]

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://lore.kernel.org/r/20250515071801.2221120-6-suraj.kandpal@intel.com