clk: qcom: dispcc-x1e80100: Fix (possibly) dumping regmap

clk: qcom: dispcc-x1e80100: Fix (possibly) dumping regmap

Reading few registers at the end of the block (e.g. 0x10000, 0x10004)
might result in synchronous external abort, so limit the regmap to the
last readable register which allows dumping the regs for debugging.

Reported-by: Daniel J Blueman <daniel@quora.org>
Closes: https://lore.kernel.org/r/CAMVG2su+V5fcZ9LOC0Qm3bpfnhpbmQdJackc7-RvfztDL_dajw@mail.gmail.com/
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Tested-by: Daniel J Blueman <daniel@quora.org>
Link: https://lore.kernel.org/r/20260505152908.302097-2-krzysztof.kozlowski@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>