ARM: dts: sti: adjust whitespace around '='

Fix whitespace coding style: use single space instead of tabs or
multiple spaces around '=' sign in property assignment.  No functional
changes (same DTB).
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Link: https://lore.kernel.org/r/20220526203632.831039-1-krzysztof.kozlowski@linaro.org