Handle percentile lists with higher precision that 2 digits

We cap the output at %2.2f right now, that's not always enough.
Make the parser check and store the precision required to
output the list correctly.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fio.h b/fio.h
index 370ddaa..43f4854 100644
--- a/fio.h
+++ b/fio.h
@@ -248,6 +248,7 @@
 	unsigned int trim_zero;
 	unsigned long long trim_backlog;
 	unsigned int clat_percentiles;
+	unsigned int percentile_precision;	/* digits after decimal for percentiles */
 	fio_fp64_t percentile_list[FIO_IO_U_LIST_MAX_LEN];
 
 	char *read_iolog_file;