hv: clean up udelay/mdelay related code

- replace the usage of mdelay with udelay
- remove lib/mdelay.c
- rename udelay.c to misc.c
  future other small APIs could put in misc.c

Tracked-On: #861
Signed-off-by: Shiqing Gao <shiqing.gao@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/lib/mdelay.c

@@ -1,18 +0,0 @@
-/*
- * Copyright (C) 2018 Intel Corporation. All rights reserved.
- *
- * SPDX-License-Identifier: BSD-3-Clause
- */
-
-#include <hv_lib.h>
-
-void mdelay(uint32_t loop_count_arg)
-{
-	uint32_t loop_count = loop_count_arg;
-	/* Loop until done */
-	while (loop_count != 0U) {
-		/* Delay for 1 ms */
-		udelay(1000U);
-		loop_count--;
-	}
-}