add execveat syscall number to microblaze

syscall number was reserved in linux v4.0, kernel commit
add4b1b02da7e7ec35c34dd04d351ac53f3f0dd8

arch/microblaze/bits/syscall.h

@@ -382,6 +382,7 @@
 #define __NR_getrandom 385
 #define __NR_memfd_create 386
 #define __NR_bpf 387
+#define __NR_execveat 388
 
 /* Repeated with SYS_ prefix */
 
@@ -770,3 +771,4 @@
 #define SYS_getrandom 385
 #define SYS_memfd_create 386
 #define SYS_bpf 387
+#define SYS_execveat 388