linux-wandboard

ENGR00279566: ARM: i.MX6: Enable L2 cache I/D prefetch function

This patch enable the L2 cache I/D prefetch function on the i.MX6 family.
Based on Android test result, it has the performance improvement:

Before the change:
JB4.3 RC1:
Browser Vellamo scores See The Sun Canvas: 51.16
Browser Vellamo scores Deep Sea Canvas: 65.41
Browser Vellamo scores Aquarium Canvas: 50.23

After the change:
Browser Vellamo scores See The Sun Canvas: 70.28
Browser Vellamo scores Deep Sea Canvas: 78.57
Browser Vellamo scores Aquarium Canvas: 53.73

Signed-off-by: Jason Liu <r64343@freescale.com>
(cherry picked from commit a51f75c318241c26bf7d41ad92c0e255b925863c)