video: fbdev: pxa3xx_gcu: fix error return code in pxa3xx_gcu_probe()

video: fbdev: pxa3xx_gcu: fix error return code in pxa3xx_gcu_probe()

platform_get_irq() returns an error code, but the pxa3xx_gcu driver
ignores it and always returns -ENODEV. This is not correct and,
prevents -EPROBE_DEFER from being propagated properly.

Also, notice that platform_get_irq() no longer returns 0 on error:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b739b18b43e38922bad573b28fa83527296f3227

Print and propagate the return value of platform_get_irq on failure.

This issue was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>