serial: qcom-geni: move resource control logic to separate functions

Supports use in PM system/runtime frameworks, helping to distinguish new
resource control mechanisms and facilitate future modifications within
the new API.

The code that handles the actual enable or disable of resources like clock
and ICC paths to a separate function (geni_serial_resources_on() and
geni_serial_resources_off()) which enhances code readability.

Introduced minor return checks in newly added function APIs to enhance
error detection and prevent silent failures.

Signed-off-by: Praveen Talari <quic_ptalari@quicinc.com>
Link: https://lore.kernel.org/r/20250721174532.14022-6-quic_ptalari@quicinc.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>