x86, traps: introduce dotraplinkage

Mark the exception handlers with "dotraplinkage" to hide the
calling convention differences between i386 and x86_64.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 977c8ea..1db6ce4 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1243,7 +1243,7 @@
 END(simd_coprocessor_error)
 
 ENTRY(device_not_available)
-	zeroentry math_state_restore
+	zeroentry do_device_not_available
 END(device_not_available)
 
 	/* runs on exception stack */