selftests: fix nested double quotes in f-string

Replace nested double quotes in f-string with outer single quotes.

Fixes: 6116075 ("selftests: nic_link_layer: Add link layer selftest for NIC driver")
Signed-off-by: David Wei <dw@davidwei.uk>
Link: https://patch.msgid.link/20241122064821.2821199-1-dw@davidwei.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: spikeh

tools/testing/selftests/drivers/net/hw/lib/py/linkconfig.py

@@ -218,5 +218,5 @@ def get_ethtool_field(self, field: str, remote: bool = False) -> Optional[str]:
         json_data = process[0]
         """Check if the field exist in the json data"""
         if field not in json_data:
-            raise KsftSkipEx(f"Field {field} does not exist in the output of interface {json_data["ifname"]}")
+            raise KsftSkipEx(f'Field {field} does not exist in the output of interface {json_data["ifname"]}')
         return json_data[field]