sdk: make sdk extraction quieter

Remove the dots that are printed while the SDK is being extracted.
These make the installer output noisy as every dot is printed on
a new line.

Change-Id: Ifc05bd09652c96164b06e880457c272ac15ce2b2
Reviewed-by: Mikko Gronoff <mikko.gronoff@qt.io>

meta-boot2qt/classes/populate_b2qt_sdk.bbclass

@@ -29,6 +29,11 @@
 
 inherit populate_sdk
 
+quiet_sdk_extraction() {
+EXTRA_TAR_OPTIONS="$EXTRA_TAR_OPTIONS --checkpoint=9999999"
+}
+SDK_PRE_INSTALL_COMMAND = "${quiet_sdk_extraction}"
+
 replace_sysroot_symlink() {
         SYMLINK_SYSROOT=$1
         SEARCH_FOLDER=$2