tools: Initially add i2c tool and mock

The power-utils will invoke i2c get/set commands to the i2c device for
PSU code update.
Create a separated i2c tool because it is logically standalone and could
be shared for other utils.
Also add an I2CInterface and its mock to make it easier to test when
developing i2c related operations.

Signed-off-by: Lei YU <mine260309@gmail.com>
Change-Id: If5383547e6d84c0a79610e2d2d6f2fa8ee9dc061
diff --git a/tools/i2c/meson.build b/tools/i2c/meson.build
new file mode 100644
index 0000000..1f4e7d1
--- /dev/null
+++ b/tools/i2c/meson.build
@@ -0,0 +1,5 @@
+libi2c_dev = static_library(
+    'i2c_dev',
+    'i2c.cpp',
+    link_args : '-li2c',
+)