rust-vmm/vhost: switch to upstream tempfile

Remove the patch that forced use of the crosvm implementation of
tempfile in favor of using the standard tempfile crate.

The ebuild for this package already depends on dev-rust/tempfile, so no
ebuild change should be necessary.

BUG=b:199204746
TEST=emerge-hatch crosvm # with patched vhost

Change-Id: If06b4251c285bfebd9c0ee70d0cb05cb026a5a37
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/rust-vmm/vhost/+/3176489
Auto-Submit: Daniel Verkamp <[email protected]>
Reviewed-by: Dennis Kempin <[email protected]>
Reviewed-by: Chirantan Ekbote <[email protected]>
Commit-Queue: Chirantan Ekbote <[email protected]>
Tested-by: Daniel Verkamp <[email protected]>
diff --git a/Cargo.toml b/Cargo.toml
index b5cb22d..e9442e3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -30,4 +30,3 @@
 
 [patch.crates-io]
 sys_util = { path = "../../../platform/crosvm/sys_util" } # ignored by ebuild
-tempfile = { path = "../../../platform/crosvm/tempfile" } # ignored by ebuild