cfi_flash: Use __func__ macro instead of function name

printf/debug statements should not include the file name as a hardcoded
string, but instead use the __func__ macro. Fix all instances where this
occurs.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
index eebd641..6ae1ac8 100644
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -555,7 +555,7 @@
 	default:
 		retval = 0;
 	}
-	debug("flash_is_busy: %d\n", retval);
+	debug("%s: %d\n", __func__, retval);
 	return retval;
 }