mlxbf_gige: return EPROBE_DEFER if PHY IRQ is not available

The message "Error getting PHY irq. Use polling instead"
is emitted when the mlxbf_gige driver is loaded by the
kernel before the associated gpio-mlxbf driver, and thus
the call to get the PHY IRQ fails since it is not yet
available. The driver probe() must return -EPROBE_DEFER
if acpi_dev_gpio_irq_get_by() returns the same.

Fixes: 6c2a6ddc ("net: mellanox: mlxbf_gige: Replace non-standard interrupt handling")
Signed-off-by: David Thompson <davthompson@nvidia.com>
Reviewed-by: Asmaa Mnebhi <asmaa@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250618135902.346-1-davthompson@nvidia.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>