powerpc: dts: add missing space before {

Add missing whitespace between node name/label and opening {.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230705145743.292855-1-krzysztof.kozlowski@linaro.org