mmap IO example mistake

[GrigorenkoPV]

diff --git a/examples/sg_simple4.c b/examples/sg_simple4.c
index 95a5023b..6f3799ad 100644
--- a/examples/sg_simple4.c
+++ b/examples/sg_simple4.c
@@ -118,7 +118,7 @@ int main(int argc, char * argv[])
     io_hdr.mx_sb_len = sizeof(sense_buffer);
     io_hdr.dxfer_direction = SG_DXFER_FROM_DEV;
     io_hdr.dxfer_len = INQ_REPLY_LEN;
-    /* io_hdr.dxferp = inqBuff; // ignored in mmap-ed IO */
+    io_hdr.dxferp = inqBuff;
     io_hdr.cmdp = inq_cdb;
     io_hdr.sbp = sense_buffer;
     io_hdr.timeout = 20000;     /* 20000 millisecs == 20 seconds */