hwmon: (ltc4286) Add missing MODULE_IMPORT_NS("PMBUS")

ltc4286.c uses PMBus core symbols exported in the PMBUS namespace,
such as pmbus_do_probe(), but does not declare MODULE_IMPORT_NS("PMBUS").

Add the missing namespace import to avoid modpost warnings.

Fixes: 0c45975 ("hwmon: (pmbus) Add ltc4286 driver")
Signed-off-by: Sanman Pradhan <psanman@juniper.net>
Link: https://lore.kernel.org/r/20260329170925.34581-5-sanman.pradhan@hpe.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Author: Sanman Pradhan

drivers/hwmon/pmbus/ltc4286.c

@@ -173,3 +173,4 @@ module_i2c_driver(ltc4286_driver);
 MODULE_AUTHOR("Delphine CC Chiu <Delphine_CC_Chiu@wiwynn.com>");
 MODULE_DESCRIPTION("PMBUS driver for LTC4286 and compatibles");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");