arm, keymile: updates for the arm based boards from keymile

define KM_IVM_BUS and KM_ENV_BUS macros
 KM_IVM_BUS is used to define the EEprom_ivm environment variable.
 These macros allow the reuse of these I2C addresses in other code
 locations.

remove unneeded code
  On first HW versions the BOCO FPGA was behind a MUX device. These
  HW versions are not supported anymore. And therefore this code can
  be removed.

added LED initialization for SUEN3
  The bootstat LED required to be initialized so to have a green
  colour after start-up.

define CONFIG_SYS_TEXT_BASE
  This is needed by the relocation code and is not the same for
  our ARM BEC and thus needs to be defined.

remove memsize variable
  An environment variable for memsize is not needed.
  this can be get via the board info struct.

remove unneeded double access to bi_dram[i].size field

Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
Signed-off-by: Luca Haab <luca.haab@keymile.com>
Signed-off-by: Heiko Schocher <hs@denx.de>
cc: Prafulla Wadaskar <prafulla@marvell.com>