platform: generic: thead: separate implement of T-HEAD c9xx errata

Separate the implement of T-HEAD c9xx errata to allow any platform
with bug related to c9xx cores can use it.

Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

platform/generic/thead/thead_c9xx_errata_tlb_flush.c

@@ -0,0 +1,17 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Authors:
+ *   Inochi Amaoto <inochiama@outlook.com>
+ *
+ */
+
+#include <sbi/riscv_encoding.h>
+#include <sbi/riscv_asm.h>
+
+void _thead_tlb_flush_fixup_trap_handler(void);
+
+void thead_register_tlb_flush_trap_handler(void)
+{
+	csr_write(CSR_MTVEC, &_thead_tlb_flush_fixup_trap_handler);
+}