interconnect: exynos: fix registration race

The current interconnect provider registration interface is inherently
racy as nodes are not added until the after adding the provider. This
can specifically cause racing DT lookups to trigger a NULL-pointer
deference when either a NULL pointer or not fully initialised node is
returned from exynos_generic_icc_xlate().

Switch to using the new API where the provider is not registered until
after it has been fully initialised.

Fixes: 2f95b9d5

 ("interconnect: Add generic interconnect driver for Exynos SoCs")
Cc: stable@vger.kernel.org      # 5.11
Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20230306075651.2449-16-johan+linaro@kernel.org
Signed-off-by: Georgi Djakov <djakov@kernel.org>