arch/arm64: skip randomization within stack

It's a WA to make 32-bit dhrystone generate consistent
scores during "sustained peformance mode" cts test.

Change-Id: Ib146224ff0701899640cbaba649227aba85534a0
Signed-off-by: Yi-wei Zhao <[email protected]>
Reviewed-on: https://gerrit.mot.com/902751
SME-Granted: SME Approvals Granted
SLTApproved: Slta Waiver <[email protected]>
Tested-by: Jira Key <[email protected]>
Reviewed-by: Igor Kovalenko <[email protected]>
Submit-Approved: Jira Key <[email protected]>
Signed-off-by: ahmedradaideh <[email protected]>

Author: Yi-wei Zhao

arch/arm64/kernel/process.c

@@ -464,8 +464,6 @@ unsigned long get_wchan(struct task_struct *p)
 
 unsigned long arch_align_stack(unsigned long sp)
 {
-	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
-		sp -= get_random_int() & ~PAGE_MASK;
 	return sp & ~0xf;
 }