tty: serial: samsung: constify UART name

The UART name from driver data holds only string literals.

Tested-by: Alim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20220308080919.152715-6-krzysztof.kozlowski@canonical.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>