misc: atmel-ssc: Fix IRQ check in ssc_probe

[ Upstream commit 1c245358 ]

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: eb1f2930

 ("Driver for the Atmel on-chip SSC on AT32AP and AT91")
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Link: https://lore.kernel.org/r/20220601123026.7119-1-linmq006@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>