mfd: stmpe: Revert "Constify static struct resource"

In stmpe_devices_init(), the start and end field of these structs are
modified, so they can not be const. Add a comment to those structs that
lacked it to reduce the risk that this happens again.

This reverts commit 8d7b3a6d.

Fixes: 8d7b3a6d

 ("mfd: stmpe: Constify static struct resource")
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>