lib: sbi_ipi: Move initial IPI clear to sbi_ipi_init()

sbi_ipi_init() expects the platform warm init function to clear IPIs
on the local hart, but there is already a generic function to do this.
After this change, none of the existing drivers need a warm init
callback.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

lib/utils/ipi/andes_plicsw.c

@@ -65,14 +65,6 @@ static struct sbi_ipi_device plicsw_ipi = {
 	.ipi_clear = plicsw_ipi_clear
 };
 
-int plicsw_warm_ipi_init(void)
-{
-	/* Clear PLICSW IPI */
-	plicsw_ipi_clear();
-
-	return 0;
-}
-
 int plicsw_cold_ipi_init(struct plicsw_data *plicsw)
 {
 	int rc;