Make Android partition table the same as for AM57x EVM.

  1. Make "bootloader" partition start from 0x300 sectors offset, so
     DRA7 is bootable in Android mode (see
     CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR option).
  2. Increase "bootloader" partition size, because size of u-boot.img is
     about 632 KiB (when building DT defconfig, with FIT image enabled).
  3. Specify "reserved" partition explicitly, rather than specifying
     "efs" partition start. Reserved area will be used to store U-Boot
     environment on eMMC. It's convenient to have it exposed explicitly
     so we can read/write U-Boot environment.
  4. Keep all Android partitions locations intact, by reducing
     "reserved" partition size. CONFIG_ENV_SIZE is considered.
Signed-off-by: NSam Protsenko <semen.protsenko@linaro.org>