MAINTAINERS: Add linux-clk patchwork URL

The common clk framework has a patchwork associated with it.
Update the maintainers file to reflect this.

Cc: Michael Turquette <mturquette@baylibre.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

MAINTAINERS

@@ -3150,6 +3150,7 @@ COMMON CLK FRAMEWORK
 M:	Michael Turquette <mturquette@baylibre.com>
 M:	Stephen Boyd <sboyd@codeaurora.org>
 L:	linux-clk@vger.kernel.org
+Q:	http://patchwork.kernel.org/project/linux-clk/list/
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git
 S:	Maintained
 F:	Documentation/devicetree/bindings/clock/