[PATCH] powerpc: Trivial fix to set the proper timeout value for kdump

The panic CPU is waiting forever due to some large timeout value if some
CPU is not responding to an IPI.
This patch fixes the problem - the maximum waiting period will be
10 seconds and then the kdump boot will go ahead.

Signed-off-by: Haren Myneni <haren@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>