tty: Remove redundant synclink driver

A note from the vendor:

 "The hardware used with synclink.c and synclinkmp.c has not been
  manufactured for 15 years and was low volume. The chances of either
  driver still being in use is very low. Not even Microgate (me) has
  the ability to test either anymore (no hardware). I don’t know the
  policy about driver removal, but I think both could be removed
  without upsetting anyone."

Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20201105123357.708813-2-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/powerpc/configs/ppc6xx_defconfig

@@ -598,7 +598,6 @@ CONFIG_GAMEPORT_FM801=m
 CONFIG_SERIAL_NONSTANDARD=y
 CONFIG_ROCKETPORT=m
 CONFIG_CYCLADES=m
-CONFIG_SYNCLINK=m
 CONFIG_SYNCLINKMP=m
 CONFIG_SYNCLINK_GT=m
 CONFIG_NOZOMI=m

drivers/tty/Kconfig

@@ -259,19 +259,6 @@ config MOXA_SMARTIO
 	  This driver can also be built as a module. The module will be called
 	  mxser. If you want to do that, say M here.
 
-config SYNCLINK
-	tristate "Microgate SyncLink card support"
-	depends on SERIAL_NONSTANDARD && PCI && ISA_DMA_API
-	help
-	  Provides support for the SyncLink ISA and PCI multiprotocol serial
-	  adapters. These adapters support asynchronous and HDLC bit
-	  synchronous communication up to 10Mbps (PCI adapter).
-
-	  This driver can only be built as a module ( = code which can be
-	  inserted in and removed from the running kernel whenever you want).
-	  The module will be called synclink.  If you want to do that, say M
-	  here.
-
 config SYNCLINKMP
 	tristate "SyncLink Multiport support"
 	depends on SERIAL_NONSTANDARD && PCI

drivers/tty/Makefile

@@ -29,7 +29,6 @@ obj-$(CONFIG_NULL_TTY)	        += ttynull.o
 obj-$(CONFIG_ROCKETPORT)	+= rocket.o
 obj-$(CONFIG_SYNCLINK_GT)	+= synclink_gt.o
 obj-$(CONFIG_SYNCLINKMP)	+= synclinkmp.o
-obj-$(CONFIG_SYNCLINK)		+= synclink.o
 obj-$(CONFIG_PPC_EPAPR_HV_BYTECHAN) += ehv_bytechan.o
 obj-$(CONFIG_GOLDFISH_TTY)	+= goldfish.o
 obj-$(CONFIG_MIPS_EJTAG_FDC_TTY) += mips_ejtag_fdc.o