www/chromium: Unbreak build on 12/aarch64

../../third_party/skia/src/core/SkCpu.cpp:84:27: error: use of undeclared identifier 'getauxval'

uint32_t hwcaps = getauxval(AT_HWCAP);
                  ^

PR: 224383
Submitted by: Mikael Urankar <mikael.urankar@gmail.com>
Reported by: jbeich