spl: fit: Always enable tracking of os-type if SPL_OS_BOOT is enabled

spl: fit: Always enable tracking of os-type if SPL_OS_BOOT is enabled

FIT_IMAGE_TINY is used to reduce the size of the SPL by removing os-type
tracking and recording the loadables into the loaded FDT. When this option
is enabled, it is assumed that the next stage firmware is u-boot.
However this does not play well with the SPL_OS_BOOT option that enables
loading different type of next stage firmware, like the OS itself.

When SPL_OS_BOOT is used, do not disable os-tracking. The added footprint
is about 300 Bytes.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>