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/libc/assert.c b/lib/libc/assert.c
index c199de6..8973ed5 100644
--- a/lib/libc/assert.c
+++ b/lib/libc/assert.c
@@ -17,16 +17,7 @@
  * LOG_LEVEL_INFO, which is the default value for builds with DEBUG=1.
  */
 
-#if PLAT_LOG_LEVEL_ASSERT >= LOG_LEVEL_VERBOSE
-void __dead2 __assert(const char *file, unsigned int line,
-		      const char *assertion)
-{
-	printf("ASSERT: %s:%u:%s\n", file, line, assertion);
-	backtrace("assert");
-	console_flush();
-	plat_panic_handler();
-}
-#elif PLAT_LOG_LEVEL_ASSERT >= LOG_LEVEL_INFO
+#if PLAT_LOG_LEVEL_ASSERT >= LOG_LEVEL_INFO
 void __dead2 __assert(const char *file, unsigned int line)
 {
 	printf("ASSERT: %s:%u\n", file, line);