spi: s3c64xx: add exynos5433 spi compatible

The samsung,exynos5433-spi has some peculiarities that bring the
need of creating a new compatible in the binding.

One of those is the 3-clocks controller management where the spi
is fed with three clocks: "spi", "busclkN" and "ioclk".

By adding the exynos5433-spi, we deprecate the exynos7 compatible
and discourage its use.

Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
Reviewed-by: Michael Turquette <mturquette@baylibre.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>