arm/tegra: Harmony PCIe: Don't touch pinmux

The Harmony pinmux table is already set up to mux the PCIe signals onto
the appropriate pin groups. Don't manually fiddle with the pinmux in the
Harmony PCIe setup code.

Merge note: This will have a merge conflict with Peter De Schrijver's
"arm/tegra: prepare pinmux code for multiple tegra variants" due to
context. When merging the two, make sure to also remove the include
of <mach/pinmux-tegra20.h> that his patch added, since it's no longer
needed after this patch.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Olof Johansson <olof@lixom.net>