ARM: OMAP2: Fix up interconnect barrier initialization for DRA7

ARM: OMAP2: Fix up interconnect barrier initialization for DRA7

The following commits:
commit a133d29fe332 ("ARM: omap2: restore OMAP4 barrier behaviour")
commit fd614c8440ea ("Revert "ARM: OMAP4: remove dead kconfig option OMAP4_ERRATA_I688"")
and
commit c4c3ca1eb938 ("ARM: DRA7: Provide proper IO map table")
came in around the same time, unfortunately this seem to have missed
initializing the barrier for DRA7 platforms - omap5_map_io was reused
for dra7 till it was split out by the last patch. barrier_init
needs to be hence carried forward as it is valid for DRA7 family of
processors as they are for OMAP5.

Fixes: c4c3ca1eb9388 ("ARM: DRA7: Provide proper IO map table")
Cc: stable@vger.kernel.org # v4.1+
Reported-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>