arm: mach-axxia: kexec_reinit to set L3 CACHE shutdown

Shut down to flush L3 cache for KEXEC to avoid the hung issue for
capture kernel booting, since for ARM capture kernel just one CPU
allowed to boot, and no L3 cache coherency issue existed for SMP
situation, so just shut down the flush to L3 CACHE.

The function calling relationship like below:
kernel_kexec
	machine_kexec
	    kexec_reinit
		flush_l3

Signed-off-by: Xulin Sun <xulin.sun@windriver.com>
[Quanyang: add a new function shutdown_l3 to shutdown the l3 cache
in the kexec routine.]
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>