vexpress64 kernels are usually over 8 MBytes in length, so setting the
max uImage length to 64 Mbytes should give us plenty of scope for
expansion.
I mostly chose this length to match other board configs that use
"(64 << 20)".
Signed-off-by: Ryan Harkin <ryan.harkin@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
0d3012af5a