ppc4xx: Add option for PPC440SPe ports without old Rev. A support

The 440SPe Rev. A is quite old and newer 440SPe boards don't need support
for this CPU revision. Since removing support for this older version
simplifies the creation for newer U-Boot ports, this patch now enables
440SPe > Rev. A support by creating the CONFIG_440SPE_REVA define. By
defining this in the board config header, Rev. A will still be supported.
Otherwise (default for newer board ports), Rev. A will not be supported.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/include/configs/yucca.h b/include/configs/yucca.h
index 42f8807..0b4dfb8 100644
--- a/include/configs/yucca.h
+++ b/include/configs/yucca.h
@@ -37,6 +37,7 @@
 #define CONFIG_4xx			1	/* ... PPC4xx family	*/
 #define CONFIG_440			1	/* ... PPC440 family	*/
 #define CONFIG_440SPE			1	/* Specifc SPe support	*/
+#define CONFIG_440SPE_REVA		1	/* Support old Rev A.	*/
 #define CONFIG_BOARD_EARLY_INIT_F	1	/* Call board_pre_init	*/
 #define CONFIG_SYS_CLK_FREQ	33333333	/* external freq to pll	*/
 #define EXTCLK_33_33		33333333