mozjs: Use vendored icu on ppc/clang

This helps compile gjs, external icu is needed with gcc-12 but not with
clang

Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-extended/mozjs/mozjs-91_91.8.0.bb

@@ -24,6 +24,7 @@ inherit pkgconfig perlnative python3native rust
 
 DEPENDS += "zlib cargo-native python3 icu"
 DEPENDS:remove:mipsarch = "icu"
+DEPENDS:remove:powerpc:toolchain-clang = "icu"
 
 B = "${WORKDIR}/build"
 
@@ -43,6 +44,7 @@ JIT ?= ""
 JIT:mipsarch = "--disable-jit"
 ICU ?= "--with-system-icu"
 ICU:mipsarch = ""
+ICU:powerpc:toolchain-clang = ""
 
 do_configure() {
     cd ${B}