arm64: dts: sprd: rename SDHCI and fuel gauge nodes to match bindings

arm64: dts: sprd: rename SDHCI and fuel gauge nodes to match bindings

DT bindings expect SDHCI/MMC nodes to be called 'mmc', rename them.
According to DT spec, node names should be generic. Rename the
sprd,sc2731-fgu node to a more generic "fuel-gauge".

Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Stanislav Jakubek <stano.jakubek@gmail.com>
Link: https://lore.kernel.org/r/861648dea0d36017327e1742ef4ef42f54b971b8.1722842067.git.stano.jakubek@gmail.com
Link: https://lore.kernel.org/r/45f5b1b8aac893d9b87c43ea76370199da4e3ff1.1722842067.git.stano.jakubek@gmail.com
[krzysztof: squash last patch for fuel gauge here, because such trivial
 node cleanups is basically one logical change]
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>