soc: ti: wkup_m3_ipc: Fix IRQ check in wkup_m3_ipc_probe

soc: ti: wkup_m3_ipc: Fix IRQ check in wkup_m3_ipc_probe

platform_get_irq() returns negative error number instead 0 on failure.
And the doc of platform_get_irq() provides a usage example:

    int irq = platform_get_irq(pdev, 0);
    if (irq < 0)
        return irq;

Fix the check of return value to catch errors correctly.

Fixes: 5a00856c4e16 ("soc: ti: Add wkup_m3_ipc driver")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Dave Gerlach <d-gerlach@ti.com>
Link: https://lore.kernel.org/r/20220114062840.16620-1-linmq006@gmail.com