tty: kconfig: remove the superfluous dependency on PPC_OF

In the current kernel, the CONFIG_PPC_OF is always 'y' for the ppc
arch. So we don't need to check it with other ppc specific options.
Signed-off-by: NKevin Hao <haokexin@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/Kconfig

@@ -835,7 +835,7 @@ config SERIAL_MCF_CONSOLE
 
 config SERIAL_PMACZILOG
 	tristate "Mac or PowerMac z85c30 ESCC support"
-	depends on (M68K && MAC) || (PPC_OF && PPC_PMAC)
+	depends on (M68K && MAC) || PPC_PMAC
 	select SERIAL_CORE
 	help
 	  This driver supports the Zilog z85C30 serial ports found on
@@ -1153,7 +1153,7 @@ config SERIAL_OMAP_CONSOLE
 
 config SERIAL_OF_PLATFORM_NWPSERIAL
 	tristate "NWP serial port driver"
-	depends on PPC_OF && PPC_DCR
+	depends on PPC_DCR
 	select SERIAL_OF_PLATFORM
 	select SERIAL_CORE_CONSOLE
 	select SERIAL_CORE