[source] lantiq: fix warning if ltq_atm modules are missing

[LEDE Commits]

mkresin pushed a commit to source.git, branch master:
https://git.lede-project.org/bececcce868eff1864c60c87c9b82cb8114510cf

commit bececcce868eff1864c60c87c9b82cb8114510cf
Author: Mathias Kresin <dev at kresin.me>
AuthorDate: Fri Feb 17 23:29:46 2017 +0100

    lantiq: fix warning if ltq_atm modules are missing
    
    Fixes the following warning on first boot if the ltq_atm modules are
    not included in the image:
    
      ls: /lib/modules/4.4.49/ltq_atm*: No such file or directory
    
    Signed-off-by: Mathias Kresin <dev at kresin.me>
---
 target/linux/lantiq/base-files/etc/board.d/02_network | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/target/linux/lantiq/base-files/etc/board.d/02_network b/target/linux/lantiq/base-files/etc/board.d/02_network
index 41d6b7f..576bb7d 100755
--- a/target/linux/lantiq/base-files/etc/board.d/02_network
+++ b/target/linux/lantiq/base-files/etc/board.d/02_network
@@ -164,9 +164,8 @@ WBMR300)
 
 esac
 
-if [ -n "$(ls /lib/modules/`uname -r`/ltq_atm*)" ]; then
+ls /lib/modules/$(uname -r)/ltq_atm* 1> /dev/null 2>&1 && \
 	ucidef_add_atm_bridge "$vpi" "$vci" "$encaps" "$payload"
-fi
 
 if lantiq_is_vdsl_system; then
 	interface_wan="ptm0"