[openwrt/openwrt] layerscape: add a make menuconfig known issue in README

[LEDE Commits]

blogic pushed a commit to openwrt/openwrt.git, branch master:
https://git.lede-project.org/f78168be62ea48a427b981ca86b8e1d49be36a55

commit f78168be62ea48a427b981ca86b8e1d49be36a55
Author: Yangbo Lu <yangbo.lu at nxp.com>
AuthorDate: Fri Jan 26 16:46:17 2018 +0800

    layerscape: add a make menuconfig known issue in README
    
    This patch is to add a known issue of make menuconfig
    in README file. This is also a common issue for OpenWrt.
    
    Signed-off-by: Yangbo Lu <yangbo.lu at nxp.com>
---
 target/linux/layerscape/README | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/target/linux/layerscape/README b/target/linux/layerscape/README
index 7415f27..c210e01 100644
--- a/target/linux/layerscape/README
+++ b/target/linux/layerscape/README
@@ -61,6 +61,12 @@ $ ./scripts/feeds install -a
   | [*] ls2088ardb-armv8_64b  --->                                  |
   +-----------------------------------------------------------------+
 
+Note: The first time make menuconfig would create a .config file which
+would include all dependencies for selected target. After that, make
+menuconfig still could be used to modify packages. If want to change
+other target, please remove .config and make menuconfig to select again.
+Otherwise the packages selected in .config would be a mess.
+
 2.2 make (or make -j<n>)
 ------------------------