psa: driver: Wrap types and symbols for C/C++ use

Add extern "C" wrappers around type and function declarations to enable C++
interoperability of the driver header. This is done so that the driver
functions and types can be used or implmented by C++ code.

include/psa/crypto_driver.h

@@ -31,6 +31,10 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /** The following types are redefinitions from the psa/crypto.h file.
  * It is intended that these will be moved to a new common header file to
  * avoid duplication. They are included here for expediency in publication.
@@ -1776,4 +1780,8 @@ typedef struct {
 
 /**@}*/
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* PSA_CRYPTO_DRIVER_H */