MIPS: alchemy: remove unused ALCHEMY_GPIOINT_AU1000

Remove unused config option ALCHEMY_GPIOINT_AU1000.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/alchemy/Kconfig

 # SPDX-License-Identifier: GPL-2.0
-# au1000-style gpio and interrupt controllers
-config ALCHEMY_GPIOINT_AU1000
-	bool
-
 choice
 	prompt "Machine type"
 	depends on MIPS_ALCHEMY
@@ -11,7 +7,6 @@ choice
 config MIPS_MTX1
 	bool "4G Systems MTX-1 board"
 	select HAVE_PCI
-	select ALCHEMY_GPIOINT_AU1000
 	select SYS_SUPPORTS_LITTLE_ENDIAN
 	select SYS_HAS_EARLY_PRINTK
 
@@ -29,13 +24,11 @@ config MIPS_DB1XXX
 
 config MIPS_XXS1500
 	bool "MyCable XXS1500 board"
-	select ALCHEMY_GPIOINT_AU1000
 	select SYS_SUPPORTS_LITTLE_ENDIAN
 	select SYS_HAS_EARLY_PRINTK
 
 config MIPS_GPR
 	bool "Trapeze ITS GPR board"
-	select ALCHEMY_GPIOINT_AU1000
 	select HAVE_PCI
 	select SYS_SUPPORTS_LITTLE_ENDIAN
 	select SYS_HAS_EARLY_PRINTK