ppc: Remove sbc8641d board

This board has not been converted to CONFIG_DM_PCI by the deadline and is
also missing conversion to CONFIG_DM.  Remove it.  This is also the last
of the ARCH_MPC8641/MPC8610 platforms, so remove that support as well.

Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Priyanka Jain <priyanka.jain@nxp.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/README b/README
index ad13092..63568dc 100644
--- a/README
+++ b/README
@@ -423,8 +423,7 @@
 
 		CONFIG_SYS_FSL_DDR
 		Freescale DDR driver in use. This type of DDR controller is
-		found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
-		SoCs.
+		found in mpc83xx, mpc85xx as well as some ARM core SoCs.
 
 		CONFIG_SYS_FSL_DDR_ADDR
 		Freescale DDR memory-mapped register base.