pinctrl: fix confusing debug message in pinctrl_register_map()

There are two types for pinctrl maps: pinmux and pinconfig
This debug message shows the number of maps of both types.
The string "pinmux map" is not precise.  Let's say "pinctrl map"
instead.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
[also fixed %d -> %u]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>