Remove unnecessary inline definition

Define inline for some compiling environment only
in crypto_platform.h.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/include/psa/crypto_types.h b/include/psa/crypto_types.h
index 864e937..ea621c1 100644
--- a/include/psa/crypto_types.h
+++ b/include/psa/crypto_types.h
@@ -37,11 +37,6 @@
 
 #include <stdint.h>
 
-#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
-    !defined(inline) && !defined(__cplusplus)
-#define inline __inline
-#endif
-
 /** \defgroup error Error codes
  * @{
  */