net: phy: Drop #inclusion of <linux/mod_devicetable.h> from <linux/mdio.h>

<linux/mdio.h> itself doesn't use any of the device id structures. The
files #including <linux/mdio.h> use a variety of them:

	$ git grep -l '<linux/mdio.h>' | xargs grep --color  -E '\<(acpi_device_id|amba_id|ap_device_id|apr_device_id|auxiliary_device_id|bcma_device_id|ccw_device_id|cdx_device_id|coreboot_device_id|css_device_id|dfl_device_id|dmi_(device|system)_id|eisa_device_id|fsl_mc_device_id|hda_device_id|hid_device_id|hv_vmbus_device_id|i2c_device_id|i3c_device_id|ieee1394_device_id|input_device_id|ipack_device_id|isapnp_device_id|ishtp_device_id|mcb_device_id|mdio_device_id|mei_cl_device_id|mhi_device_id|mips_cdmm_device_id|of_device_id|parisc_device_id|pci_device_id|pci_epf_device_id|pcmcia_device_id|platform_device_id|pnp_(card_)?device_id|rio_device_id|rpmsg_device_id|sdio_device_id|sdw_device_id|serio_device_id|slim_device_id|spi_device_id|spmi_device_id|ssam_device_id|ssb_device_id|tb_service_id|tee_client_device_id|typec_device_id|ulpi_device_id|usb_device_id|vchiq_device_id|virtio_device_id|wmi_device_id|x86_(cpu|device)_id|zorro_device_id|cpu_feature)\>'
	...

but none of them relies on <linux/mdio.h>'s #include.

<linux/mod_devicetable.h> is a bad header mixing many different device
id structures and thus is an unfortunate dependency because if e.g.
struct wmi_device_id is modified all users of <linux/mdio.h> need to be
recompiled despite none of them using struct wmi_device_id.

So drop the unused header.

Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/ca270a534d0f230a939a3fb4a661808b35d6436d.1783329817.git.u.kleine-koenig@baylibre.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

include/linux/mdio.h

@@ -8,7 +8,6 @@
 
 #include <uapi/linux/mdio.h>
 #include <linux/bitfield.h>
-#include <linux/mod_devicetable.h>
 
 struct gpio_desc;
 struct mii_bus;