refactor(libc): clean up dependencies in libc

- Removing platform dependencies from libc modules.
- Replacing panicking with actual error handling.
- Debug macros are included indirectly from assert.h. Removing
  "platform_def.h" from assert.h and adding "common/debug.h"
  where the macros are used.
- Removing hack for fixing PLAT_LOG_LEVEL_ASSERT to 40.
  Instead removing assert with expression, as this
  does not provide additional information.

Signed-off-by: Claus Pedersen <claustbp@google.com>
Change-Id: Icc201ea7b63c1277e423c1cfd13fd6816c2bc568
diff --git a/lib/optee/optee_utils.c b/lib/optee/optee_utils.c
index d30248f..6c87b0d 100644
--- a/lib/optee/optee_utils.c
+++ b/lib/optee/optee_utils.c
@@ -9,6 +9,8 @@
 #include <common/debug.h>
 #include <lib/optee_utils.h>
 
+#include <platform_def.h>
+
 /*
  * load_addr_hi and load_addr_lo: image load address.
  * image_id: 0 - pager, 1 - paged