package/freescale-imx: update SITE to directly use https

http://www.nxp.com/ has a redirect to https://www.nxp.com/ for quite
some time now. It is also quite common to directly hit https:// urls
now.

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/freescale-imx/freescale-imx.mk

@@ -4,6 +4,6 @@
 #
 ################################################################################
 
-FREESCALE_IMX_SITE = http://www.nxp.com/lgfiles/NMG/MAD/YOCTO
+FREESCALE_IMX_SITE = https://www.nxp.com/lgfiles/NMG/MAD/YOCTO
 
 include $(sort $(wildcard package/freescale-imx/*/*.mk))