In this case the secure code lives in RAM, and hence the memory node in
the device tree needs to be adjusted. This avoids that the OS will map
and possibly access the reservation.

Add support for setting CONFIG_ARMV7_SECURE_RESERVE_SIZE to carve out
such a region. We only support cutting off memory from the beginning or
the end of a RAM bank as we do not want to increase their number (which
would happen if punching a hole) for simplicity reasons

This will be used in a subsequent patch for Jetson-TK1.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>