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/plat/nxp/soc-ls1046a/ls1046aqds/ddr_init.c b/plat/nxp/soc-ls1046a/ls1046aqds/ddr_init.c
index 6d1707c..89c9c0a 100644
--- a/plat/nxp/soc-ls1046a/ls1046aqds/ddr_init.c
+++ b/plat/nxp/soc-ls1046a/ls1046aqds/ddr_init.c
@@ -12,6 +12,7 @@
 #include <lib/utils.h>
 
 #include <errata.h>
+#include "platform_def.h"
 
 static const struct rc_timing rce[] = {
 	{U(1600), U(8), U(7)},