tty: serial: drop ATH79 specific SoC symbols

QCA MIPS support is being converted to pure OF. As part of this we are
dropping the SOC_AR* symbols. Additionally the SERIAL_AR933X style tty
is also found on a few SoCs newer that the AR933x.

This patch changes the dependency to ATH79, thus fixing the 2 issues
described above.
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/Kconfig

@@ -1294,7 +1294,7 @@ config SERIAL_XILINX_PS_UART_CONSOLE
 
 config SERIAL_AR933X
 	tristate "AR933X serial port support"
-	depends on HAVE_CLK && SOC_AR933X
+	depends on HAVE_CLK && ATH79
 	select SERIAL_CORE
 	help
 	  If you have an Atheros AR933X SOC based board and want to use the