[source] remove bogus dev/null that was accidentally introduced while applying a patch

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/0e7869f20492a76fc1f331101fa01bfe9f02692f

commit 0e7869f20492a76fc1f331101fa01bfe9f02692f
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Thu Nov 24 13:42:58 2016 +0100

    remove bogus dev/null that was accidentally introduced while applying a patch
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 dev/null | 0
 1 file changed, 0 insertions(+), 0 deletions(-)

diff --git a/dev/null b/dev/null
deleted file mode 100644
index e69de29..0000000