exynos5420: Enable relocatable module support

Since we're now supporting ARMv7 relocations, we can enable
rmodule support on Exynos 5420. This does not automatically
enable relocatable ramstage.

Signed-off-by: Stefan Reinauer <reinauer@google.com>

Change-Id: Ic3af1eabb3b816944587a46409224f778d941b8a
Reviewed-on: https://chromium-review.googlesource.com/167403
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: Stefan Reinauer <reinauer@google.com>
Commit-Queue: Stefan Reinauer <reinauer@google.com>
(cherry picked from commit 7b5afef4ee87fc3245ec887dfda873c529d8d04d)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6629
Tested-by: build bot (Jenkins)
Reviewed-by: David Hendricks <dhendrix@chromium.org>