meta-digi-arm: remove u-boot preferred versions

There is only one u-boot supported for each platform, so there is no
need to explicitly set the u-boot preferred version.

As a result it was needed to rework the nvram recipe which was using the
removed PREFERRED_VERSION_u-boot-dey variable.

Signed-off-by: Javier Viguera <javier.viguera@digi.com>

meta-digi-arm/conf/machine/include/digi-defaults.inc

@@ -14,9 +14,6 @@ PREFERRED_PROVIDER_virtual/xserver = "xserver-xorg"
 # ccardimx28    3.10               2013.01
 # ccimx6        3.14               2015.04
 #
-# Digi BSP default versions
-PREFERRED_VERSION_u-boot-dey ?= "2013.01"
-PREFERRED_VERSION_u-boot-dey_ccimx5 ?= "2009.08"
 
 # Help variables used in recipes
 HAVE_WIFI    = "${@base_contains('MACHINE_FEATURES', 'wifi', '1', '', d)}"

meta-digi-arm/recipes-bsp/nvram/nvram.inc

@@ -5,7 +5,7 @@ SECTION = "base"
 LICENSE = "GPL-2.0"
 LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/GPL-2.0;md5=801f80980d171dd6425610833a22dbe6"
 
-require recipes-bsp/u-boot/u-boot-dey-rev_${PREFERRED_VERSION_u-boot-dey}.inc
+require recipes-bsp/u-boot/u-boot-dey-rev_${PV}.inc
 
 DEPENDS = "libdigi"
 

meta-digi-arm/recipes-bsp/nvram/nvram_2009.08.bb

@@ -0,0 +1,5 @@
+PV = "2009.08"
+
+require recipes-bsp/nvram/nvram.inc
+
+COMPATIBLE_MACHINE = "(ccimx5)"

meta-digi-arm/recipes-bsp/nvram/nvram_2013.01.bb

@@ -0,0 +1,5 @@
+PV = "2013.01"
+
+require recipes-bsp/nvram/nvram.inc
+
+COMPATIBLE_MACHINE = "(ccardimx28)"