buildroot

kexec: bump to 2.0.16

In 2.0.16 we now have uncompressed kernel size available
for ARM starting v4.14 and later kernels.

Let's also remove the extra space after the checksum while at it.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>