[Buildroot] [git commit] php: use $() to reference make variables instead of ${}

[Peter Korsgaard]

>>>>> "Arnout" == Arnout Vandecappelle (Essensium/Mind) <arnout at mind.be> writes:

 > commit: https://git.buildroot.net/buildroot/commit/?id=dba254cdf006e559ed61e1a136677843a3b4a94e
 > branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/master

 > Signed-off-by: Ricardo Martincoski <ricardo.martincoski at gmail.com>
 > Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout at mind.be>

Committed to 2018.02.x and 2018.05.x, thanks.

-- 
Bye, Peter Korsgaard