perf syscalltbl: Mask off ABI type for MIPS system calls

Arnd Bergmann described that MIPS system calls don't necessarily start
from 0 as an ABI prefix is applied:
https://lore.kernel.org/lkml/[e-mail]/
When decoding the "id" (aka system call number) for MIPS ignore values
greater-than 1000.

Signed-off-by: Ian Rogers <[e-mail]>
Reviewed-by: Namhyung Kim <[e-mail]>
Acked-by: Arnaldo Carvalho de Melo <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Namhyung Kim <[e-mail]>

tools/perf/util/syscalltbl.c

···
 {
 	const struct syscalltbl *table = find_table(e_machine);
 
+	if (e_machine == EM_MIPS && id > 1000) {
+		/*
+		 * MIPS may encode the N32/64/O32 type in the high part of
+		 * syscall number. Mask this off if present. See the values of
+		 * __NR_N32_Linux, __NR_64_Linux, __NR_O32_Linux and __NR_Linux.
+		 */
+		id = id % 1000;
+	}
 	if (table && id >= 0 && id < table->num_to_name_len)
 		return table->num_to_name[id];
 	return NULL;