powerpc: Remove unused REDBOOT Kconfig parameter

This removes the REDBOOT Kconfig parameter,
which was no longer used anywhere in the source code
and Makefiles.
Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/Kconfig

@@ -209,9 +209,6 @@ config DEFAULT_UIMAGE
 	  Used to allow a board to specify it wants a uImage built by default
 	default n
 
-config REDBOOT
-	bool
-
 config ARCH_HIBERNATION_POSSIBLE
 	bool
 	default y

arch/powerpc/platforms/83xx/Kconfig

@@ -99,7 +99,6 @@ config SBC834x
 config ASP834x
 	bool "Analogue & Micro ASP 834x"
 	select PPC_MPC834x
-	select REDBOOT
 	help
 	  This enables support for the Analogue & Micro ASP 83xx
 	  board.

arch/powerpc/platforms/8xx/Kconfig

@@ -45,7 +45,6 @@ config PPC_EP88XC
 config PPC_ADDER875
 	bool "Analogue & Micro Adder 875"
 	select CPM1
-	select REDBOOT
 	help
 	  This enables support for the Analogue & Micro Adder 875
 	  board.