riscv: xtheadbb: Fix xtheadbb-li-rotr test for rv32

The test was introduced recently and tests a RV64-only feature.
However, when testing an RV32 compiler, the test gets executed as well
and fails with "cc1: error: ABI requires '-march=rv32'".
This patch fixes this by adding '-mabi=lp64' (like it is done for
other RV64-only tests as well).

Retested with RV32 and RV64 to ensure this won't pop up again.

Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/xtheadbb-li-rotr.c: Don't run for RV32.

gcc/testsuite/gcc.target/riscv/xtheadbb-li-rotr.c

@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=rv64gc_xtheadbb" } */
+/* { dg-options "-march=rv64gc_xtheadbb -mabi=lp64" } */
 /* { dg-skip-if "" { *-*-* } {"-O0" "-Os" "-Og" "-Oz" "-flto" } } */
 /* { dg-final { check-function-bodies "**" "" } } */