lib: utils/ipi: add T-Head C9xx CLINT compatible

backport commit a8ee82cd8c008f09c91b5c307de4c9b37660ff71 upstream

Althoug the MTIMER part of a C9xx CLINT differs from a SiFive one, the
MSWI part is compliant.

Add T-Head C9xx CLINT compatible string to fdt_ipi_mswi code, sharing
the same codepath with SiFive CLINT.

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Reviewed-by: Anup Patel <anup@brainfault.org>

lib/utils/ipi/fdt_ipi_clint.c

@@ -37,6 +37,7 @@ static int ipi_clint_cold_init(void *fdt, int nodeoff,
 static const struct fdt_match ipi_clint_match[] = {
 	{ .compatible = "riscv,clint0" },
 	{ .compatible = "sifive,clint0" },
+	{ .compatible = "thead,c900-clint" },
 	{ },
 };