pinctrl: mvebu: armada-{370,375,38x,39x,xp}: normalize TDM pins

This commit normalizes the naming of the TDM pins accross the
different Marvell SoCs. Mainly it consists in:

 * Removing the 'n' from signal names: 'intn' becomes 'int' and 'rstn'
   becomes 'rst'

 * Renaming the main name 'tdm2c' to 'tdm' on Armada 38x.

 * Change the main name 'tdm-1' to 'tdm' for one of the pins of the
   Armada XP

The last two changes affect DT compatibility, but since the TDM
interface is nowhere near being supported in mainline, it should not
be considered to be a serious problem at this point.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>