bcma: Replace mdelay with usleep_range in bcma_pmu_resources_init

After checking all possible call chains to bcma_pmu_resources_init() here,
my tool finds that this function is never called in atomic context,
namely never in an interrupt handler or holding a spinlock.
Thus mdelay can be replaced with usleep_range to avoid busy wait.

This is found by a static analysis tool named DCNS written by myself.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/bcma/driver_chipcommon_pmu.c

@@ -203,7 +203,7 @@ static void bcma_pmu_resources_init(struct bcma_drv_cc *cc)
 	 * Add some delay; allow resources to come up and settle.
 	 * Delay is required for SoC (early init).
 	 */
-	mdelay(2);
+	usleep_range(2000, 2500);
 }
 
 /* Disable to allow reading SPROM. Don't know the adventages of enabling it. */