lib: sbi: Simplify ipi platform operations

Instead of having ipi_send() and ipi_clear() callbacks in
platform operations, it will be much simpler for ipi driver
to directly register these operations as a device to sbi_ipi
implementation.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

platform/sifive/fu540/platform.c

@@ -158,8 +158,6 @@ const struct sbi_platform_operations platform_ops = {
 	.final_init		= fu540_final_init,
 	.console_init		= fu540_console_init,
 	.irqchip_init		= fu540_irqchip_init,
-	.ipi_send		= clint_ipi_send,
-	.ipi_clear		= clint_ipi_clear,
 	.ipi_init		= fu540_ipi_init,
 	.get_tlbr_flush_limit	= fu540_get_tlbr_flush_limit,
 	.timer_init		= fu540_timer_init,