tests/tcg/xtensa: only generate defined exception handlers

Don't generate handlers for IRQ levels that are not defined for the CPU
or for window overflow/underflow exceptions for configs w/o windowed
registers.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

tests/tcg/xtensa/vectors.S

@@ -1,3 +1,5 @@
+#include "core-isa.h"
+
 .macro vector name
 
 .section .vector.\name
@@ -20,19 +22,33 @@ handler_\name\(): .word 0
 
 .endm
 
+#if XCHAL_HAVE_WINDOWED
 vector window_overflow_4
 vector window_overflow_8
 vector window_overflow_12
 vector window_underflow_4
 vector window_underflow_8
 vector window_underflow_12
+#endif
 
+#if XCHAL_NUM_INTLEVELS + XCHAL_HAVE_NMI >= 2
 vector level2
+#endif
+#if XCHAL_NUM_INTLEVELS + XCHAL_HAVE_NMI >= 3
 vector level3
+#endif
+#if XCHAL_NUM_INTLEVELS + XCHAL_HAVE_NMI >= 4
 vector level4
+#endif
+#if XCHAL_NUM_INTLEVELS + XCHAL_HAVE_NMI >= 5
 vector level5
+#endif
+#if XCHAL_NUM_INTLEVELS + XCHAL_HAVE_NMI >= 6
 vector level6
+#endif
+#if XCHAL_NUM_INTLEVELS + XCHAL_HAVE_NMI >= 7
 vector level7
+#endif
 
 vector kernel
 vector user