pinctrl: make a copy of pinmux map

This makes a deep copy of the pinmux function map instead of
keeping the copy supplied from the platform around. This makes
it possible to tag the platforms map with __initdata as is also
done as part of this patch.

Rationale: a certain target platform (PXA) has numerous
pinmux maps, many of which will be lying around unused after
boot in a multi-platform binary. Instead, deep-copy the one
we're going to use and tag them all __initdata so they go away
after boot.

ChangeLog v1->v2:
- Fixup the deep copy, missed a few items on the struct,
  plus mark bool member non-const since we're making runtime
  copies if this stuff now.
ChangeLog v2->v3:
- Make a shallow copy (just copy the array of map structs)
  as Arnd noticed, string constants never get discarded by the
  kernel anyway, so these pointers may be safely copied over.

Reviewed-by: Arnd Bergmann <arnd.bergmann@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/pinctrl.txt

@@ -697,7 +697,7 @@ spi on the second function mapping:
 
 #include <linux/pinctrl/machine.h>
 
-static const struct pinmux_map pmx_mapping[] = {
+static const struct pinmux_map __initdata pmx_mapping[] = {
 	{
 		.ctrl_dev_name = "pinctrl.0",
 		.function = "spi0",
@@ -734,7 +734,7 @@ Since the above construct is pretty common there is a helper macro to make
 it even more compact which assumes you want to use pinctrl.0 and position
 0 for mapping, for example:
 
-static struct pinmux_map pmx_mapping[] = {
+static struct pinmux_map __initdata pmx_mapping[] = {
        PINMUX_MAP_PRIMARY("I2CMAP", "i2c0", "foo-i2c.0"),
 };