Add programmer-specific delay functions

Add external programmer delay functions so external programmers can
handle the delay on their own if needed.

Corresponding to flashrom svn r578.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
Acked-by: Urja Rannikko <urjaman@gmail.com>
diff --git a/m29f002.c b/m29f002.c
index 78cdc75..8ad86d2 100644
--- a/m29f002.c
+++ b/m29f002.c
@@ -29,7 +29,7 @@
 	chip_writeb(0xaa, bios + 0x555);
 	chip_writeb(0x55, bios + 0xaaa);
 	chip_writeb(0x10, bios + 0x555);
-	myusec_delay(10);
+	programmer_delay(10);
 	toggle_ready_jedec(bios);
 	return 0;
 }
@@ -44,7 +44,7 @@
 	chip_writeb(0xaa, bios + 0x555);
 	chip_writeb(0x55, bios + 0xaaa);
 	chip_writeb(0x30, dst);
-	myusec_delay(10);
+	programmer_delay(10);
 	toggle_ready_jedec(bios);
 
 	/* program */