uboot-imx

MA-16048 Fix imx8q u-boot hang

Address 0x8880_0000 is reserved for M4 image on imx8q, which
leaves limited memory region for the malloc pool. The avb
will consume much heap memory to verify the kernel and dtbo
image, memory conflicts may happen as the kernel/dtbo image
size is getting larger.

As the avb will load kernel/dtbo in every avb_slot_verify(), but
will only free the memory after both slots are checked(if needed).
And for trusty enabled platforms, extra heap memory will be used
to do the hash calculation.

This commit will free the slot memory once it's marked as unbootable
and will use fixed memory started from CONFIG_FASTBOOT_BUF_ADDR to
help store the data to do the hash calculation. With above change,
we get a chance to decrease the malloc pool size.

Test: boot on imx8qxp and imx8mm.

Change-Id: Ia5cdaf9962ae1cb8b8e9bee5305205ec6d90b84a
Signed-off-by: Ji Luo <ji.luo@nxp.com>