of: Add array read functions with min/max size limits

Add a new set of array reading functions that take a minimum and
maximum size limit and will fail if the property size is not within
the size limits. This makes it more convenient for drivers that
use variable-size DT arrays which must be bounded at both ends -
data must be at least N entries but must not overflow the array
it is being copied into. It is also more efficient than making this
functionality out of existing public functions and avoids duplication.

The existing array functions have been left in the API, since there
are a very large number of clients of those functions and their
existing functionality is still useful. This avoids turning a small
API improvement into a major kernel rework.

The old functions have been turned into mininmal static inlines calling
the new functions. The old functions had no upper limit on the actual
size of the dts entry, to preserve this functionality rather than keeping
two near-identical implementations, if the new function is called with
max=0 there is no limit on the size of the dts entry but only the min
number of elements are read.

Signed-off-by: Richard Fitzgerald <rf@opensource.wolfsonmicro.com>
Signed-off-by: Rob Herring <robh@kernel.org>