symbols-check: discard platform symbols early

(as the comment there already claimed)

Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Tested-by: Vinson Lee <vlee@freedesktop.org>

bin/symbols-check.py

@@ -27,6 +27,8 @@ def get_symbols(nm, lib):
                                      stderr=open(os.devnull, 'w')).decode("ascii")
     for line in output.splitlines():
         (_, _, symbol_name) = line.split()
+        if symbol_name in PLATFORM_SYMBOLS:
+            continue
         symbols.append(symbol_name)
     return symbols
 
@@ -97,8 +99,6 @@ def main():
             continue
         if symbol in optional_symbols:
             continue
-        if symbol in PLATFORM_SYMBOLS:
-            continue
         unknown_symbols.append(symbol)
 
     missing_symbols = [