tty: powerpc: remove SERIAL_ICOM dependency on PPC_ISERIES

The PowerPC legacy iSeries platform is being removed so this is no
longer selectable.

Cc: Alan Cox <alan@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-serial@vger.kernel.org
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/tty/serial/Kconfig

@@ -853,7 +853,7 @@ config SERIAL_MPC52xx_CONSOLE_BAUD
 
 config SERIAL_ICOM
 	tristate "IBM Multiport Serial Adapter"
-	depends on PCI && (PPC_ISERIES || PPC_PSERIES)
+	depends on PCI && PPC_PSERIES
 	select SERIAL_CORE
 	select FW_LOADER
 	help