[RISCV] Avoid save-restore target feature warning

Summary:
LLVM issues a warning if passed unknown target features. Neither I nor
@asb noticed this until after https://reviews.llvm.org/D63498 landed.

This patch stops passing the (unknown) "save-restore" target feature to
the LLVM backend, but continues to emit a warning if a driver asks for
`-msave-restore`. The default of assuming `-mno-save-restore` (and
emitting no warnings) remains.

Reviewers: asb

Reviewed By: asb

Subscribers: rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, kito-cheng, shiva0217, jrtc27, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, Jim, cfe-commits, asb

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64008

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@364777 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Driver/riscv-features.c b/test/Driver/riscv-features.c
index edd57c3..44fb59b 100644
--- a/test/Driver/riscv-features.c
+++ b/test/Driver/riscv-features.c
@@ -17,9 +17,5 @@
 // RUN: %clang -target riscv32-unknown-elf -### %s -mno-save-restore 2>&1 | FileCheck %s -check-prefix=NO-SAVE-RESTORE
 
 // SAVE-RESTORE: warning: the clang compiler does not support '-msave-restore'
-// DEFAULT-NOT: warning: the clang compiler does not support
-
-// SAVE-RESTORE: "-target-feature" "+save-restore"
-// NO-SAVE-RESTORE: "-target-feature" "-save-restore"
-// DEFAULT: "-target-feature" "-save-restore"
-// DEFAULT-NOT: "-target-feature" "+save-restore"
\ No newline at end of file
+// NO-SAVE-RESTORE-NOT: warning: the clang compiler does not support
+// DEFAULT-NOT: warning: the clang compiler does not support
\ No newline at end of file