i2c: Add binding for MCTP over I2C transport

Implements DSP0237. This has a fixed neighbor table (currently 4
entries), with neighbors learned on reception, or set with
mctp_i2c_set_neighbour().

Change-Id: I9b1e2c3673149cd0b9fee0d8113f3cac0e336bc7
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
diff --git a/meson.options b/meson.options
index fda6e56..e3d9f9c 100644
--- a/meson.options
+++ b/meson.options
@@ -8,8 +8,8 @@
     'bindings',
     type: 'array',
     description: 'Bindings to include',
-    choices: ['serial', 'astlpc'],
-    value: ['serial', 'astlpc'],
+    choices: ['serial', 'astlpc', 'i2c'],
+    value: ['serial', 'astlpc', 'i2c'],
 )
 option(
     'default_alloc',