ARM: imx: add an exclusive gate clock type

There are a couple of gate clocks are mutually exclusive on i.MX6, i.e.
LVDSCLK1_IBEN and LVDSCLK1_OBEN.  They cannot be enabled simultaneously.
This patches adds an exclusive gate clock type specifically for such
case.  The clock driver will need to call imx_clk_gate_exclusive() to
register a gate clock with parameter exclusive_mask indicating the mask
of gate bits which are mutually exclusive to this gate clock.

Right now, it only handles the exclusive gate clocks which are defined
in a single hardware register, which is the case we're running into
today.  But it can be extended to handle exclusive gate clocks defined
in different registers later if needed.

Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile
index ef215d1..6e4fcd8 100644
--- a/arch/arm/mach-imx/Makefile
+++ b/arch/arm/mach-imx/Makefile
@@ -16,7 +16,8 @@
 
 obj-$(CONFIG_COMMON_CLK) += clk-pllv1.o clk-pllv2.o clk-pllv3.o clk-gate2.o \
 			    clk-pfd.o clk-busy.o clk.o \
-			    clk-fixup-div.o clk-fixup-mux.o
+			    clk-fixup-div.o clk-fixup-mux.o \
+			    clk-gate-exclusive.o
 
 obj-$(CONFIG_IMX_HAVE_IOMUX_V1) += iomux-v1.o
 obj-$(CONFIG_ARCH_MXC_IOMUX_V3) += iomux-v3.o