pnor_partition_table: Make writeUserdata() private to namespace

This is part of the ongoing effort to extract parseTocLine() from the
Table class, enabling reuse in setup for test cases.

Change-Id: I846e67b728df7bf57fd132b21438a13248d426fc
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/pnor_partition_table.cpp b/pnor_partition_table.cpp
index 997876d..9c9fb9c 100644
--- a/pnor_partition_table.cpp
+++ b/pnor_partition_table.cpp
@@ -96,7 +96,7 @@
     }
 }
 
-inline void Table::writeUserdata(pnor_partition& part, uint32_t version,
+static inline void writeUserdata(pnor_partition& part, uint32_t version,
                                  const std::string& data)
 {
     std::istringstream stream(data);
diff --git a/pnor_partition_table.hpp b/pnor_partition_table.hpp
index 4dcc864..9d254d8 100644
--- a/pnor_partition_table.hpp
+++ b/pnor_partition_table.hpp
@@ -182,18 +182,6 @@
      */
     void writeSizes(pnor_partition& part, size_t start, size_t end);
 
-    /** @brief Populate userdata bits for the input
-     *         pnor_partition structure.
-     *
-     *  @param[in/out] part - pnor_partition structure
-     *  @param[in] version - partition version check algorithm to be used
-     *                       (see pnor_partition_defs.h)
-     *  @param[in] data - string having userdata fields in a
-     *             comma-separated line.
-     */
-    void writeUserdata(pnor_partition& part, uint32_t version,
-                       const std::string& data);
-
     /** @brief Return a little-endian partition table
      *
      *  @returns reference to native partition table