Revert "generic: revert to OpenWrt CC partition sizes on x86 and similar images for now"

This reverts commit fcce9e529501e5952d8c62dae0fe009f36ad2878.

The x86-generic kernel does not fit into 4MB.

targets/generic

@@ -11,9 +11,6 @@ config 'CONFIG_PACKAGE_ATH_DEBUG=y'
 config 'CONFIG_TARGET_MULTI_PROFILE=y'
 config 'CONFIG_TARGET_PER_DEVICE_ROOTFS=y'
 
-config 'CONFIG_TARGET_KERNEL_PARTSIZE=4'
-config 'CONFIG_TARGET_ROOTFS_PARTSIZE=48'
-
 if [ "$GLUON_DEBUG" ]
 then
 	config 'CONFIG_DEBUG=y'