arm64: dts: qcom: sc7280: split TCSR halt regs out of mutex

The TCSR halt regs are next to TCSR mutex (in one address block called
TCSR_MUTEX), so before converting the TCSR mutex into device with
address space, we need to split the halt regs to its own syscon device.
This also describes more accurately the devices and their IO address
space, and allows to remove incorrect syscon compatible from TCSR mutex:

  qcom/sc7280-herobrine-crd.dtb: hwlock@1f40000: compatible: ['qcom,tcsr-mutex', 'syscon'] is too long

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220819083209.50844-10-krzysztof.kozlowski@linaro.org