crosvm: set ARM_TRIPLE to armv7a-cros-linux-gnueabihf
crosvm: set ARM_TRIPLE to armv7a-cros-linux-gnueabihf

This changes ARM_TRIPLE to armv7a-cros-linux-gnueabihf because we are
renaming the abi from armv7a-cros-linux-gnueabi to armv7a-cros-linux-gnueabihf

BUG=chromium:711369
TEST=FEATURES="test" emerge-kevin crosvm

Change-Id: I4b4352f7cba47ba6492e733dd1d16796dadd3275
Reviewed-on: https://chromium-review.googlesource.com/1241538
Commit-Ready: ChromeOS CL Exonerator Bot <fa429e5907f00867f797423aea74327bb02c91b6@appspot.gserviceaccount.com>
Tested-by: Yunlian Jiang <8ca9e07d8da722742b3f5a8340e0afab8cf1248e@chromium.org>
Reviewed-by: Manoj Gupta <1d49d0f302d724a1dc5fc4d717d15418e9808ddd@chromium.org>
Reviewed-by: Chirantan Ekbote <35787c0e27de5c48735e07f8324823b765e8bcbc@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm