soc: qcom: socinfo: fix revision check in qcom_socinfo_probe()

soc: qcom: socinfo: fix revision check in qcom_socinfo_probe()

In success case, the revision holds a non-null pointer. The current
logic incorrectly returns an error for a non-null pointer, whereas
it should return an error for a null pointer.

The socinfo driver for IPQ9574 and IPQ5332 is currently broken,
resulting in the following error message
qcom-socinfo qcom-socinfo: probe with driver qcom-socinfo failed with
error -12

Add a null check for the revision to ensure it returns an error only in
failure case (null pointer).

Fixes: e694d2b5c58b ("soc: qcom: Add check devm_kasprintf() returned value")
Signed-off-by: Manikanta Mylavarapu <quic_mmanikan@quicinc.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20241016144852.2888679-1-quic_mmanikan@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>