RFC: tolerate junk after valid initramfs

At the moment, the initramfs handling code will reject a valid initramfs if there is junk between the end of the valid initramfs and the initramfs size given to the kernel.

For example passing initrd=0x01000000,4M will not work unless the initramfs is either exactly 4M in size or is padded with zeroes up to 4M.

As those working with ARM processors might know, the initialization code in the bootloader generally doesn't zero out unused memory, so that memory will contain garbage.

What downsides are there to patching init/initramfs.c to have the kernel accept valid initramfs images where the image is shorter than the length passed to the kernel by the bootloader?