MAINTAINERS: pinctrl: Add maintainers for pinctrl-single

Otherwise we keep missing patches related to this driver.

Cc: Haojian Zhuang <haojian.zhuang@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

MAINTAINERS

@@ -8379,6 +8379,14 @@ L:	linux-samsung-soc@vger.kernel.org (moderated for non-subscribers)
 S:	Maintained
 F:	drivers/pinctrl/samsung/
 
+PIN CONTROLLER - SINGLE
+M:	Tony Lindgren <tony@atomide.com>
+M:	Haojian Zhuang <haojian.zhuang@linaro.org>
+L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
+L:	linux-omap@vger.kernel.org
+S:	Maintained
+F:	drivers/pinctrl/pinctrl-single.c
+
 PIN CONTROLLER - ST SPEAR
 M:	Viresh Kumar <vireshk@kernel.org>
 L:	spear-devel@list.st.com