mm: optimize thread stack usage on ARMv7 [1/1]

mm: optimize thread stack usage on ARMv7 [1/1]

PD#SWPL-2681

Problem:
Kernel stack usage is large when running many tasks.

Solution:
Map kernel stack to module space and handle page-fault
for stack fault. This can save about 50% memory of stack
usage

Verify:
p212

Change-Id: Ie894bc8f00cb525ddf8ac63c6d99d9c6e937fdc0
Signed-off-by: tao zeng <tao.zeng@amlogic.com>