mailbox: pcc: Fix spelling mistake "Plaform" -> "Platform"

There is a spelling mistake in a pr_err message. Fix it.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

drivers/mailbox/pcc.c

@@ -676,7 +676,7 @@ static int pcc_mbox_probe(struct platform_device *pdev)
 
 		if (pcct_entry->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE &&
 		    !pcc_mbox_ctrl->txdone_irq) {
-			pr_err("Plaform Interrupt flag must be set to 1");
+			pr_err("Platform Interrupt flag must be set to 1");
 			rc = -EINVAL;
 			goto err;
 		}