pantech: fix warnings with -Wdiscarded-qualifiers
pantech/mm-plugin-pantech.c:69:7: error: initialization discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers]
69 | { "ATE0", 3, port_probe_response_processor_is_pantech_at },
| ^~~~~~
pantech/mm-plugin-pantech.c:70:7: error: initialization discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers]
70 | { "ATE0", 3, port_probe_response_processor_is_pantech_at },
| ^~~~~~
pantech/mm-plugin-pantech.c:71:7: error: initialization discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers]
71 | { "ATE0", 3, port_probe_response_processor_is_pantech_at },
| ^~~~~~