Move up to mbed TLS 2.x

The mbed TLS library has introduced some changes in the API from
the 1.3.x to the 2.x releases. Using the 2.x releases requires
some changes to the crypto and transport modules.

This patch updates both modules to the mbed TLS 2.x API.

All references to the mbed TLS library in the code or documentation
have been updated to 'mbed TLS'. Old references to PolarSSL have
been updated to 'mbed TLS'.

User guide updated to use mbed TLS 2.2.0.

NOTE: moving up to mbed TLS 2.x from 1.3.x is not backward compatible.
Applying this patch will require an mbed TLS 2.x release to be used.
Also note that the mbed TLS license changed to Apache version 2.0.

Change-Id: Iba4584408653cf153091f2ca2ee23bc9add7fda4
diff --git a/drivers/auth/mbedtls/mbedtls_common.mk b/drivers/auth/mbedtls/mbedtls_common.mk
index b71bbc9..bc381d5 100644
--- a/drivers/auth/mbedtls/mbedtls_common.mk
+++ b/drivers/auth/mbedtls/mbedtls_common.mk
@@ -31,7 +31,7 @@
 ifneq (${MBEDTLS_COMMON_MK},1)
 MBEDTLS_COMMON_MK	:=	1
 
-# MBEDTLS_DIR must be set to the mbedTLS main directory (it must contain
+# MBEDTLS_DIR must be set to the mbed TLS main directory (it must contain
 # the 'include' and 'library' subdirectories).
 ifeq (${MBEDTLS_DIR},)
   $(error Error: MBEDTLS_DIR not set)
@@ -40,9 +40,9 @@
 INCLUDES		+=	-I${MBEDTLS_DIR}/include		\
 				-Iinclude/drivers/auth/mbedtls
 
-# Specify mbedTLS configuration file
-POLARSSL_CONFIG_FILE	:=	"<mbedtls_config.h>"
-$(eval $(call add_define,POLARSSL_CONFIG_FILE))
+# Specify mbed TLS configuration file
+MBEDTLS_CONFIG_FILE	:=	"<mbedtls_config.h>"
+$(eval $(call add_define,MBEDTLS_CONFIG_FILE))
 
 MBEDTLS_COMMON_SOURCES	:=	drivers/auth/mbedtls/mbedtls_common.c	\
 				$(addprefix ${MBEDTLS_DIR}/library/,	\