x86: Increase SYS_MALLOC_F_LEN to 0x1000
A few x86 platforms use a SYS_MALLOC_F_LEN value of 0x1000 or higher.
With the impending move to having DEVRES enabled by default, we will
need a little more room here. Raise the default value.
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>