vtable: avoid ambiguity in method

When flags are passed to the method interface there is ambiguity
between the method with flag and the method with offset.  Rename
method with offset to method_o, which matches the pattern of other
vtable interfaces.

Change-Id: I9c2c501ffcf391b839c4e604025ca22d6c9acdbe
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/sdbusplus/vtable.hpp b/sdbusplus/vtable.hpp
index dccadca..7d9dfe8 100644
--- a/sdbusplus/vtable.hpp
+++ b/sdbusplus/vtable.hpp
@@ -37,9 +37,10 @@
  *  @param[in] offset - Offset.
  *  @param[in] flags - optional sdbusplus::vtable::method_ value.
  */
-constexpr vtable_t method(const char* member, const char* signature,
-                          const char* result, sd_bus_message_handler_t handler,
-                          size_t offset, decltype(vtable_t::flags) flags = 0);
+constexpr vtable_t method_o(const char* member, const char* signature,
+                            const char* result,
+                            sd_bus_message_handler_t handler,
+                            size_t offset, decltype(vtable_t::flags) flags = 0);
 
 /** Create a SD_BUS_SIGNAL entry.
  *
@@ -133,12 +134,13 @@
                           const char* result, sd_bus_message_handler_t handler,
                           decltype(vtable_t::flags) flags)
 {
-    return method(member, signature, result, handler, 0, flags);
+    return method_o(member, signature, result, handler, 0, flags);
 }
 
-constexpr vtable_t method(const char* member, const char* signature,
-                          const char* result, sd_bus_message_handler_t handler,
-                          size_t offset, decltype(vtable_t::flags) flags)
+constexpr vtable_t method_o(const char* member, const char* signature,
+                            const char* result,
+                            sd_bus_message_handler_t handler,
+                            size_t offset, decltype(vtable_t::flags) flags)
 {
     vtable_t v{};
     v.type = _SD_BUS_VTABLE_METHOD;