asterisk: replace $(HOST_DIR)/usr/bin with $(HOST_DIR)/bin

Commit 0f9c0bf3 did a global replace of $(HOST_DIR)/usr/bin to
$(HOST_DIR)/bin. But later, a new occurrence of $(HOST_DIR)/usr/bin snuck
into the sources via commit 05e306d8 which added asterisk.

Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>