Draft: [BOOTSCRIPT] integrate new bootscript

Integrates the new bootscript and boot environment architecture into rpi machines.

Specifically, this commit:

• sets bootscript parameters in layer.conf
• adds boot_hw.env which disables loading of fdt from mmc (fdt is initialized by the firmware)
• add hw bootscript that sets up the fdt and bootargs, and copies u-boot variables to clea os variables for compatibility
• adds a patch that sets up the boot environment and CONFIG_BOOTCOMMAND
• fixes bootscript recipe PROVIDES value

Signed-off-by: Alessandro Pecugi alessandro.pecugi@seco.com