firefox: Move AS=${CC} to mozilla_run_mach()

After oe-core toolchain changes, this isn't passed through, so it needs
to be specified in the shell function.

Signed-off-by: Calvin Owens <calvin@wbinvd.org>

Author: jcalvinowens

meta-firefox/classes/mozilla.bbclass

@@ -41,6 +41,7 @@ mozilla_run_mach() {
 	export SHELL="/bin/sh"
 	export RUSTFLAGS="${RUSTFLAGS} -Clinker=${WORKDIR}/wrapper/target-rust-ccld --sysroot=${RECIPE_SYSROOT}"
 
+	export AS="${CC}"
 	export RUST_HOST=${RUST_HOST}
 	export RUST_TARGET=${RUST_TARGET}
 

meta-firefox/recipes-browser/firefox/firefox.inc

@@ -121,7 +121,6 @@ SRC_URI += "${@bb.utils.contains('PACKAGECONFIG', 'forbid-multiple-compositors',
            ', '', d)}"
 
 TOOLCHAIN:pn-firefox = "clang"
-AS = "${CC}"
 
 DISABLE_STATIC = ""