BugLink: https://bugs.launchpad.net/bugs/1848598

[ Upstream commit c2cf351e ]

pmx_writel uses writel which inserts write barrier before the
register write.

This patch has fix to replace writel with writel_relaxed followed
by a readback and memory barrier to ensure write operation is
completed for successful pinctrl change.
Acked-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Link: https://lore.kernel.org/r/1565984527-5272-2-git-send-email-skomatineni@nvidia.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>