fix(bl31): fix validate_el3_interrupt_rm preprocessor usage

Fix the "#if defined(FOO)" usage introduced by commit 7c2fe62f1
("fix(bl31): allow use of EHF with S-EL2 SPMC") since the defines are
always passed as -DFOO=0 or as -DFOO=1. The "#if defined(FOO)" will now
always be true which is wrong.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Change-Id: I84fb144debc9899727a1fc021acdd59b4a6f0171
diff --git a/include/bl31/interrupt_mgmt.h b/include/bl31/interrupt_mgmt.h
index 694f1f0..21af112 100644
--- a/include/bl31/interrupt_mgmt.h
+++ b/include/bl31/interrupt_mgmt.h
@@ -107,7 +107,7 @@
 
 static inline int32_t validate_el3_interrupt_rm(uint32_t x)
 {
-#if defined (EL3_EXCEPTION_HANDLING) && !(defined(SPD_spmd) && (SPMD_SPM_AT_SEL2 == 1))
+#if EL3_EXCEPTION_HANDLING && !(defined(SPD_spmd) && (SPMD_SPM_AT_SEL2 == 1))
 	/*
 	 * With EL3 exception handling, EL3 interrupts are always routed to EL3
 	 * from both Secure and Non-secure, when the SPMC does not live in S-EL2.