accel/amdxdna: Add expandable device heap support

accel/amdxdna: Add expandable device heap support

Introduce an expandable device heap to avoid allocating a large heap
upfront. Start with a smaller initial heap and grow it on demand.
Return -EAGAIN when BO allocation fails due to insufficient heap space,
allowing userspace to trigger heap expansion via a heap BO creation
IOCTL and retry the allocation.

Manage heap chunks using an xarray. On expansion, register new chunks
with the firmware via MSG_OP_ADD_HOST_BUFFER.

Since heap shrinking is not supported by the firmware, release all heap
chunks on device close.

Co-developed-by: Wendy Liang <wendy.liang@amd.com>
Signed-off-by: Wendy Liang <wendy.liang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Link: https://patch.msgid.link/20260515161922.744647-1-lizhi.hou@amd.com