ARM: mmu: Set domain permissions to client access

 The 'XN' execute never bit is set in the pagetables. This will
 prevent speculative prefetches to non executable regions. But the
 domain permissions are set as master in the DACR register.
 So the pagetable attribute for 'XN' is not effective. Change the
 permissions to client.

 This fixes lot of speculative prefetch aborts seen on OMAP5
 secure devices.

Signed-off-by: R Sricharan <r.sricharan@ti.com>
Tested-by: Vincent Stehle <v-stehle@ti.com>
Cc: Vincent Stehle <v-stehle@ti.com>
Cc: Tom Rini <trini@ti.com>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>