MIPS: Kconfig: remove "config MIPS_DISABLE_OBSOLETE_IDE"

The Kconfig symbol MIPS_DISABLE_OBSOLETE_IDE was added in v2.6.10. It
has never been used. Let's remove it.

The symbol was originally introduced by the following commit

commit 2bfa662b64a7ee593f3039c1d3fd81a7766a63cd
Author: Pete Popov <ppopov@embeddedalley.com>
Date:   Tue Oct 12 06:24:19 2004 +0000
    - Db1550 bug fixes
    - updated defconfig
    - updated Kconfig to use DMA_COHERENT since new silicon is coherent
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Patchwork: http://patchwork.linux-mips.org/patch/5064/Acked-by: John Crispin <blogic@openwrt.org>

arch/mips/Kconfig

@@ -981,9 +981,6 @@ config MIPS_MSC
 config MIPS_NILE4
 	bool
 
-config MIPS_DISABLE_OBSOLETE_IDE
-	bool
-
 config SYNC_R4K
 	bool
 

arch/mips/alchemy/Kconfig

@@ -31,7 +31,6 @@ config MIPS_DB1000
 	select ALCHEMY_GPIOINT_AU1000
 	select DMA_NONCOHERENT
 	select HW_HAS_PCI
-	select MIPS_DISABLE_OBSOLETE_IDE
 	select SYS_SUPPORTS_BIG_ENDIAN
 	select SYS_SUPPORTS_LITTLE_ENDIAN
 	select SYS_HAS_EARLY_PRINTK
@@ -41,7 +40,6 @@ config MIPS_DB1235
 	select ARCH_REQUIRE_GPIOLIB
 	select HW_HAS_PCI
 	select DMA_COHERENT
-	select MIPS_DISABLE_OBSOLETE_IDE
 	select SYS_SUPPORTS_LITTLE_ENDIAN
 	select SYS_HAS_EARLY_PRINTK
 
@@ -57,7 +55,6 @@ config MIPS_GPR
 	select ALCHEMY_GPIOINT_AU1000
 	select HW_HAS_PCI
 	select DMA_NONCOHERENT
-	select MIPS_DISABLE_OBSOLETE_IDE
 	select SYS_SUPPORTS_LITTLE_ENDIAN
 	select SYS_HAS_EARLY_PRINTK