spi: microchip-core: Clean up redundant dev_err_probe()

Refering to platform_get_irq()'s definition, the return value has
already been checked if ret < 0, and printed via dev_err_probe().
Calling dev_err_probe() one more time outside platform_get_irq()
is obviously redundant.

Furthermore, platform_get_irq() will never return irq equals 0,
removing spi->irq == 0 checking to clean it up.

Signed-off-by: Chen Jiahao <chenjiahao16@huawei.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230728075729.3451867-1-chenjiahao16@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>