usb: dwc3: qcom: simplify error check in dwc3_qcom_find_num_ports()

usb: dwc3: qcom: simplify error check in dwc3_qcom_find_num_ports()

The platform_get_irq_byname_optional() function returns a non-zero
IRQ number on success and a negative error code on failure. It
never returns zero.

The current implementation in the modern dwc3-qcom driver checks for
a return value less than or equal to zero. Since zero is not a
valid return value, simplify the check to only look for negative
error codes. This aligns the logic with the standard return contract
of the platform IRQ APIs.

Signed-off-by: Zeeshan Ahmad <zeeshanahmad022019@gmail.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://patch.msgid.link/20260225065157.8952-1-zeeshanahmad022019@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>