Merge "riscv64: say "x3" rather than "gp" in shadow call stack assembler." am: ad333b6161

Original change: https://android-review.googlesource.com/c/platform/bionic/+/2592806

Change-Id: Iecb8a9afcd273face3901ac5efef3fcc4c3f2a71
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>