selftest/bpf: Enable instruction array test for powerpc

With instruction array now supported, enable corresponding bpf
selftest for powerpc.

Signed-off-by: Abhishek Dubey <adubey@linux.ibm.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20260401152133.42544-3-adubey@linux.ibm.com

Author: Abhishek Dubey

tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c

@@ -3,7 +3,7 @@
 #include <bpf/bpf.h>
 #include <test_progs.h>
 
-#ifdef __x86_64__
+#if defined(__x86_64__) || defined(__powerpc__)
 static int map_create(__u32 map_type, __u32 max_entries)
 {
 	const char *map_name = "insn_array";