Suppress Cppcheck syntax errors

Cppcheck cannot recognize the GNU extension of explicit register
variables:
  register int x asm("eax");

This commit suppresses syntax error to prevent explicit register
variables being blocked. It also makes real syntax error suppressed, but
it doesn't affect much while real ones lead to compile-time errors and
can be found early.

Change-Id: I603fa80083ba935c7de706546f77bac616da6fcc

Author: lumynou5

scripts/pre-commit.hook

@@ -26,6 +26,7 @@ cppcheck_suppressions() {
     "missingIncludeSystem"
     "noValidConfiguration"
     "unusedFunction"
+    "syntaxError"
     "identicalInnerCondition:log2_lshift16.h"
     "checkLevelNormal:log2_lshift16.h"
     "nullPointerRedundantCheck:report.c"