qemu: suppress spurious 'make' output when printing kernel version

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Pascal Brand <pascal.brand@linaro.org>
diff --git a/qemu.mk b/qemu.mk
index 1b1930e..ecd73c7 100644
--- a/qemu.mk
+++ b/qemu.mk
@@ -29,7 +29,7 @@
 # defines, macros, configuration etc
 ################################################################################
 define KERNEL_VERSION
-$(shell cd $(LINUX_PATH) && make kernelversion)
+$(shell cd $(LINUX_PATH) && $(MAKE) --no-print-directory kernelversion)
 endef
 
 CCACHE ?= $(shell which ccache) # Don't remove this comment (space is needed)