powerpc/40x: remove unused "config 405GPR"

The last user of Kconfig symbol 405GPR got removed in release v3.2.
Remove this symbol too.
Signed-off-by: NPaul Bolle <pebolle@tiscali.nl>
Acked-by: NJosh Boyer <jwboyer@gmail.com>
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>

arch/powerpc/platforms/40x/Kconfig

@@ -119,9 +119,6 @@ config 405EZ
 	select IBM_EMAC_MAL_CLR_ICINTSTAT
 	select IBM_EMAC_MAL_COMMON_ERR
 
-config 405GPR
-	bool
-
 config XILINX_VIRTEX
 	bool
 	select DEFAULT_UIMAGE