kexec,x86: Use macro CRASH_MAX_MEMMAP_NR for clarification

[Simon Horman]

On Tue, Feb 26, 2013 at 06:12:54PM +0800, Zhang Yanfei wrote:
> For the allocation, using CRASH_MAX_MEMMAP_NR instead of KEXEC_MAX_SEGMENTS + 1 
> seems more understandable.

Thanks, applied.