prereqs: Remove zlibc from the package list

Verilator doesn't seem to actually depend on this package, and it's no
longer available in Debian testing, so it was breaking our prereqs
script.

Change-Id: I37fec17e051684be7093188f9974eef2fec0ce01

install-prereqs.sh

diff --git a/install-prereqs.sh b/install-prereqs.sh
index 7fc9e2e..310957e 100755
--- a/install-prereqs.sh
+++ b/install-prereqs.sh
@@ -86,7 +86,6 @@
     policykit-1
     screen
     wget
-    zlibc
     zlib1g
     zlib1g-dev
 )