am335x: Initial support for Silica Pengwyn board

This patch add support for the Silica Pengwyn board [1]
The board is based on a TI AM3354 CPU [2]
All jumpers removed it will boot from the SDcard, the console is on
UART1 accessible via the FDTI -> USB. The on board NAND flash is
supported and can act as boot medium, depending on jumper settings.
USB Host, USB Device and Ethernet are also provided but untested.

[1]
http://www.silica.com/product/silica-pengwyn-board.html
[2]
http://www.ti.com/product/am3354

Signed-off-by: Lothar Felten <lothar.felten@gmail.com>
[trini: Move CONFIG_BOARD_LATE_INIT into am335x_evm.h, drop unused
spi0_pin_mux from Pengwyn support]
Signed-off-by: Tom Rini <trini@ti.com>
diff --git a/boards.cfg b/boards.cfg
index 0e663d9..e917753 100644
--- a/boards.cfg
+++ b/boards.cfg
@@ -256,6 +256,7 @@
 Active  arm         armv7          am33xx      siemens         dxr2                dxr2                                 -                                                                                                                                 Roger Meier <r.meier@siemens.com>
 Active  arm         armv7          am33xx      siemens         pxm2                pxm2                                 -                                                                                                                                 Roger Meier <r.meier@siemens.com>
 Active  arm         armv7          am33xx      siemens         rut                 rut                                  -                                                                                                                                 Roger Meier <r.meier@siemens.com>
+Active  arm         armv7          am33xx      silica          pengwyn             pengwyn                              -                                                                                                                                 Lothar Felten <lothar.felten@gmail.com>
 Active  arm         armv7          am33xx      ti              am335x              am335x_boneblack                     am335x_evm:SERIAL1,CONS_INDEX=1,EMMC_BOOT                                                                                         Tom Rini <trini@ti.com>
 Active  arm         armv7          am33xx      ti              am335x              am335x_evm                           am335x_evm:SERIAL1,CONS_INDEX=1,NAND                                                                                              Tom Rini <trini@ti.com>
 Active  arm         armv7          am33xx      ti              am335x              am335x_evm_nor                       am335x_evm:SERIAL1,CONS_INDEX=1,NAND,NOR                                                                                          Tom Rini <trini@ti.com>