Don't pass the stack pointer to zImage's start() function

[Olaf Hering]

On Thu, Mar 15, David Gibson wrote:

> At present, the zImage entry code passes a copy of the stack pointer
> to the start() function.  There's no real reason for this; the only
> thing start() does with it is print it out.  It appears to be a
> leftover debugging hack, so, this patch removes it.
> 
> Signed-off-by: David Gibson <david at gibson.dropbear.id.au>

NACK.
It helps to determine the firmware memory layout.