pinctrl: intel: merrifield: fix dup size in probe

In function mrfld_pinctrl_probe(), when duplicating the mrfld_families
array the requested memory region length is multiplied once too many by the
number of elements in the original array. Fix this to spare some memory.

Fixes: 4e80c8f5 ("pinctrl: intel: Add Intel Merrifield pin controller support")
Signed-off-by: Vincent Stehlé <vincent.stehle@intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>