Add PIXIS FPGA support for MPC8641HPCN board.

Move the 8641HPCN's PIXIS code to the new directory
board/freescale/common/ as it will be shared by
future boards not in the same processor family.

Write a "pixis_reset" command that utilizes the FPGA
reset sequencer to support alternate soft-reset options
such as using the "alternate" flash bank, enabling
the watch dog, or choosing different CPU frequencies.

Add documentation for the pixis_reset to README.mpc8641hpcn.

Signed-off-by: Haiying Wang <haiying.wang@freescale.com>
Signed-off-by: Jon Loeliger <jdl@freescale.com>
diff --git a/cpu/mpc86xx/cpu.c b/cpu/mpc86xx/cpu.c
index 551b243..84f5bef 100644
--- a/cpu/mpc86xx/cpu.c
+++ b/cpu/mpc86xx/cpu.c
@@ -32,12 +32,6 @@
 #include <ft_build.h>
 #endif
 
-#ifdef CONFIG_MPC8641HPCN
-extern void mpc8641_reset_board(cmd_tbl_t *cmdtp, int flag,
-				int argc, char *argv[]);
-#endif
-
-
 int
 checkcpu(void)
 {
@@ -185,7 +179,7 @@
 
 #else /* CONFIG_MPC8641HPCN */
 
-	mpc8641_reset_board(cmdtp, flag, argc, argv);
+	out8(PIXIS_BASE + PIXIS_RST, 0);
 
 #endif /* !CONFIG_MPC8641HPCN */