conf/machine: bump max_leb_cnt for am3
conf/machine: bump max_leb_cnt for am3

Previous commit meant to increase it more than just by 200...

Signed-off-by: Denys Dmytriyenko <d29de71aea38aad3a87d486929cb0aad173ae612@ti.com>

rcn-ee/meta-ti,rcn-ee/meta-ti,rcn-ee/meta-ti,rcn-ee/meta-ti