keystone-evm: Update NAND size to 512 MB
keystone-evm: Update NAND size to 512 MB

- The keystone-evm actually has 512 MB Nand
   ( Changing from previous size of 128 MB)
- LEB calculated with reserved 10 MB for boot and 20 MB
  for receovery image

Signed-off-by: Sam Nelson <922b89dc606ff5f34a79f0527810322597be4ea8@ti.com>
Signed-off-by: Denys Dmytriyenko <d29de71aea38aad3a87d486929cb0aad173ae612@ti.com>

jumpnow/meta-ti,jumpnow/meta-ti