BUILD: Look at current_cpu instead of target_cpu
BUILD: Look at current_cpu instead of target_cpu

Fixes build error where fuchsia_arm64 builds were failing because they
picked up linux x86 code.

Bug: None
Change-Id: I48a7bc92490604fd2a59cb4d36421cb76f579224
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/2172636
Reviewed-by: Joshua Peraza <f5809a5e35ec7e1bd0e25cb0a0b68bb433cf6f17@chromium.org>
Commit-Queue: Ian Barkley-Yeung <57078f1f26922dfa7c93d7ff5e296d6fef6a23b5@chromium.org>

chromium/crashpad,chromium/crashpad,chromium/crashpad