PM / OPP: Remove ARCH_HAS_OPP

PM / OPP: Remove ARCH_HAS_OPP

Since the OPP layer is a kernel library which has been converted to be
directly selectable by its callers rather than user selectable and
requiring architectures to enable it explicitly the ARCH_HAS_OPP symbol
has become redundant and can be removed. Do so.

Signed-off-by: Mark Brown <[email protected]>
Reviewed-by: Viresh Kumar <[email protected]>
Acked-by: Nishanth Menon <[email protected]>
Acked-by: Rob Herring <[email protected]>
Acked-by: Shawn Guo <[email protected]>
Acked-by: Simon Horman <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>