kselftest/arm64: Fix redundancy of a testcase

Currently, we are writing the same value as we read into the TLS
register, hence we cannot confirm update of the register, making the
testcase "verify_tpidr_one" redundant. Fix this.

Signed-off-by: Dev Jain <[email protected]>
Reviewed-by: Mark Brown <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[[email protected]: remove the increment style change]
Signed-off-by: Catalin Marinas <[email protected]>

Author: Dev Jain

tools/testing/selftests/arm64/abi/ptrace.c

@@ -47,7 +47,7 @@ static void test_tpidr(pid_t child)
 
 	/* ...write a new value.. */
 	write_iov.iov_len = sizeof(uint64_t);
-	write_val[0] = read_val[0]++;
+	write_val[0] = read_val[0] + 1;
 	ret = ptrace(PTRACE_SETREGSET, child, NT_ARM_TLS, &write_iov);
 	ksft_test_result(ret == 0, "write_tpidr_one\n");