arm,davinci: update for enbw_cmc board

- change gpio pin settings:

  - gpio pin 6[13] (PLC reset) default value low
  - gpio pin 6[0] (TPM reset) default value low
  - 4 new GPIO pins
      pin  i/o   name
    - 3[9] input Board Type
    - 2[7] input HW-ID0
    - 2[6] input HW-ID1
    - 2[3] input HW-ID2

- read board type and hw id from gpio pins on the enbw_cmc board,
  and use board type for setting up different gpio pin settings.

- do not pass "davinci_mmc.use_dma=0" to linux, as MMC now
  works with DMA.

- update logbuf support:
  store post word in RTC scratch register

- add support for configuring KSZ8864RMN switch through
  a config file on u-boot startup. For more infos see:
  doc/README.switch_config

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Tom Rini <tom.rini@gmail.com>
Cc: Christian Riesch <christian.riesch@omicron.at>
Cc: Sandeep Paulraj <s-paulraj@ti.com>
diff --git a/doc/README.switch_config b/doc/README.switch_config
new file mode 100644
index 0000000..f890373
--- /dev/null
+++ b/doc/README.switch_config
@@ -0,0 +1,25 @@
+On the enbw_cmc board is a KSZ8864RMN switch which needs
+configured through spi before working. This is done on
+startup from u-boot through a config file stored at an
+address specified in the "hwconfig" environment variable,
+subcommand "config".
+
+For example on the enbw_cmc board:
+
+hwconfig=switch:lan=on,pwl=off,config=0x60160000
+
+The file has the following structure:
+
+- a comment starts with a '#' or a ';' and ends with a newline
+- The switch needs for its config a reg/value pair, so we
+  have two columns in the file:
+    reg  : contains the register address
+    value: contains a 8 bit register value
+  This 2 columns are seperated through space or tab.
+
+example (minimal configuration on the enbw_cmc board):
+
+;reg    value   comment
+;-----------------------------------------
+0x01	0x00
+0x01	0x01    ; Start Switch with this configuration