ipq806x: Add support for GPIO operations

Basic support for ipq806x GPIO CFG and IO reg operations
Reference: IPQ806x PRM, u-boot arch-ipq806x/gpio.*
BUG=None
BRANCH=None
TEST=Compiled successfully

Original-Change-Id: Ia0a9f288de3ac7bdb1cd4acbf44ba46af4dcc4e2
Original-Reviewed-on: https://chromium-review.googlesource.com/194217
Original-Tested-by: Furquan Shaikh <furquan@chromium.org>
Original-Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
Original-Commit-Queue: Furquan Shaikh <furquan@chromium.org>
(cherry picked from commit 0b48e6655e63b467fe79d52149be01d23a2a3712)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I09e222f35b4b20c8eb901f33cf4451085c4c99cc
Reviewed-on: http://review.coreboot.org/7266
Tested-by: build bot (Jenkins)
Reviewed-by: David Hendricks <dhendrix@chromium.org>
4 files changed