fix(sdei): fix assert while kdump issue

Assert condition:
1 Register secure timer(ppi=29) for sdei nmi watchdog;
2 kernel panic and then kdump;
While kdump, kernel mask all cores sdei, secure timer trigger
and go to handle_masked_trigger() and assert here:
assert(se->affinity == my_mpidr);

As kernel register with flag=0, mpidr=0 and TF-A set flag to
SDEI_REGF_RM_PE but leave mpidr=0. So set mpidr to fix his
assert issue.

Signed-off-by: Ming Huang <huangming@linux.alibaba.com>
Change-Id: Ia9182f40bde94fb004b46e2a72b186eb0ef05166

services/std_svc/sdei/sdei_main.c

@@ -359,8 +359,20 @@ static int64_t sdei_event_register(int ev_num,
 		return SDEI_EINVAL;
 
 	/* Private events always target the PE */
-	if (is_event_private(map))
+	if (is_event_private(map)) {
+		/*
+		 * SDEI internally handles private events in the same manner
+		 * as public events with routing mode=RM_PE, since the routing
+		 * mode flag and affinity fields are not used when registering
+		 * a private event, set them here.
+		 */
 		flags = SDEI_REGF_RM_PE;
+		/*
+		 * Kernel may pass 0 as mpidr, as we set flags to
+		 * SDEI_REGF_RM_PE, so set mpidr also.
+		 */
+		mpidr = read_mpidr_el1();
+	}
 
 	se = get_event_entry(map);