rpi: increase SYS_BOOTM_LEN to 64M on ARM64

On AArch64, kernel images are not self-decompressing and easily exceed
the 8MB limit.

Signed-off-by: Laurent Bonnans <laurent.bonnans@here.com>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>
1 file changed