ARM: tegra: pinctrl: remove duplication

ARM: tegra: pinctrl: remove duplication

Much of arch/arm/cpu/tegra*-common/pinmux.c is identical. Remove the
duplication by creating pinmux-common.c for all the identical code.

This leaves:
* arch/arm/include/asm/arch-tegra*/pinmux.h defining only the names of
  the various pins/pin groups, drive groups, and mux functions.
* arch/arm/cpu/tegra*-common/pinmux.c containing only the lookup table
  stating which pin groups support which mux functions.

The code in pinmux-common.c is semantically identical to that in the
various original pinmux.c, but had some consistency and cleanup fixes
applied during migration.

I removed the definition of struct pmux_tri_ctlr, since this is different
between SoCs (especially Tegra20 vs all others), and it's much simpler to
deal with this via the new REG/MUX_REG/... defines. spl.c, warmboot.c,
and warmboot_avp.c needed updates due to this, since they previously
hijacked this struct to encode the location of some non-pinmux registers.
Now, that code simply calculates these register addresses directly using
simple and obvious math. I like this method better irrespective of the
pinmux code cleanup anyway.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>