ARM: dts: exynos: use define for TMU clock on Exynos4412

Replace clock hard-coded number with a define from bindings.  No
functional change.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Link: https://lore.kernel.org/r/20220122131457.63304-1-krzysztof.kozlowski@canonical.com