[openwrt/openwrt] layerscape: update build guide in README

[LEDE Commits]

blogic pushed a commit to openwrt/openwrt.git, branch master:
https://git.lede-project.org/5f36f3193f793d9963d01da6796dcbb8d10edc99

commit 5f36f3193f793d9963d01da6796dcbb8d10edc99
Author: Yangbo Lu <yangbo.lu at nxp.com>
AuthorDate: Mon Jan 8 12:12:16 2018 +0800

    layerscape: update build guide in README
    
    Added package feeds updating and installing in build guide
    of README.
    
    Signed-off-by: Yangbo Lu <yangbo.lu at nxp.com>
---
 target/linux/layerscape/README | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/target/linux/layerscape/README b/target/linux/layerscape/README
index eaeee32..ecef32b 100644
--- a/target/linux/layerscape/README
+++ b/target/linux/layerscape/README
@@ -12,6 +12,10 @@ Layerscape Quick Start
 
 2. Build
 --------
+Before configuration and build, update and install package feeds.
+
+$ ./scripts/feeds update -a
+$ ./scripts/feeds install -a
 
 2.1 make menuconfig
 -------------------