[source] procd: nand: make it possible to configure kernel and ubi partition

[LEDE Commits]

blogic pushed a commit to source.git, branch master:
https://git.lede-project.org/93aa8604052305830ea6801f0b93ffe2f0d55721

commit 93aa8604052305830ea6801f0b93ffe2f0d55721
Author: Christian Lamparter <chunkeey at gmail.com>
AuthorDate: Sun Nov 20 03:33:03 2016 +0100

    procd: nand: make it possible to configure kernel and ubi partition
    
    With this patch, the nand.sh script no longer overwrites
    CI_KERNELPART and CI_UBIPART if they have been set before.
    
    This allows platforms specify alternative values for these
    variables.
    
    Signed-off-by: Christian Lamparter <chunkeey at gmail.com>
---
 package/system/procd/files/nand.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/package/system/procd/files/nand.sh b/package/system/procd/files/nand.sh
index ebaaf2a..01dba61 100644
--- a/package/system/procd/files/nand.sh
+++ b/package/system/procd/files/nand.sh
@@ -5,10 +5,10 @@
 . /lib/functions.sh
 
 # 'kernel' partition on NAND contains the kernel
-CI_KERNPART="kernel"
+CI_KERNPART="${CI_KERNPART:-kernel}"
 
 # 'ubi' partition on NAND contains UBI
-CI_UBIPART="ubi"
+CI_UBIPART="${CI_UBIPART:-ubi}"
 
 ubi_mknod() {
 	local dir="$1"