package/cdrkit: fix namespace of variables

Not all cdrkit variables are prefixed with CDRKIT_, so they leak.

Most importantly, they look like they belong to another package's
namespace, cmake, as they start with CMAKE_ (but fortunately, they
have no impact on cmake, as they are not used by our infras.)

Fix that by removing the intermediate variables, and directly set
the CDRKIT_CONF_OPT variable.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas De Schampheleire <patrickdepinguin@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/cdrkit/cdrkit.mk

@@ -11,13 +11,11 @@ CDRKIT_LICENSE = GPLv2
 CDRKIT_LICENSE_FILES = COPYING
 
 ifeq ($(BR2_ENDIAN),"BIG")
-CMAKE_ENDIAN_OPT=-DBITFIELDS_HTOL=1
+CDRKIT_CONF_OPT += -DBITFIELDS_HTOL=1
 else
-CMAKE_ENDIAN_OPT=-DBITFIELDS_HTOL=0
+CDRKIT_CONF_OPT += -DBITFIELDS_HTOL=0
 endif
 
-CDRKIT_CONF_OPT += $(CMAKE_ENDIAN_OPT)
-
 ## cdrkit isn't completely re-rooted by CMAKE_FIND_ROOT_PATH, so add
 ## some extra flags so it finds needed libs and headers.
 CDRKIT_CONF_OPT += -DCMAKE_C_FLAGS="-I$(STAGING_DIR)/usr/include"