test: dm: clk_ccf: test ccf_clk_ops

Assign ccf_clk_ops to .ops of clk_ccf driver so that it can act as an
clk provider. Also add "#clock-cells=<1>" to its device tree node.

Add "i2c_root" to clk_test in the device tree and driver for testing.

Get "i2c_root" clock in CCF unit tests and add tests for it.

Signed-off-by: Yang Xiwen <forbidden405@outlook.com>
Reviewed-by: Sean Anderson <seanga2@gmail.com>
Link: https://lore.kernel.org/r/20231111-enable_count-v3-2-08a821892fa9@outlook.com
diff --git a/arch/sandbox/include/asm/clk.h b/arch/sandbox/include/asm/clk.h
index df7156f..1daf2e7 100644
--- a/arch/sandbox/include/asm/clk.h
+++ b/arch/sandbox/include/asm/clk.h
@@ -39,6 +39,7 @@
 	SANDBOX_CLK_TEST_ID_FIXED,
 	SANDBOX_CLK_TEST_ID_SPI,
 	SANDBOX_CLK_TEST_ID_I2C,
+	SANDBOX_CLK_TEST_ID_I2C_ROOT,
 	SANDBOX_CLK_TEST_ID_DEVM1,
 	SANDBOX_CLK_TEST_ID_DEVM2,
 	SANDBOX_CLK_TEST_ID_DEVM_NULL,