kmemleak: Fix bad memory access with scan stack for amlogic vmap

kmemleak: Fix bad memory access with scan stack for amlogic vmap

When AMLOGIC_VMAP is enabled, try_get_task_stack() returns address
of stasck instead of page address. This causes bad memory access
during kmemleak scan stack. Fix the bad memory access by using
aml_task_stack().

Note: Maybe, get_task_stack() needs to call aml_task_stack() is
required, but aml_task_stack() has no consideration for kmalloced
task stack, so just fix from kmemleak.

Change-Id: I58a2e324cb92cd692d2260c675e81d7d0715e96c
Fixes: commit 4d6ae4359385 ("mm: optimize thread stack usage on arm64 [1/1]")
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>