bcma: change delays to follow timers-howto guide

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/bcma/core.c b/drivers/bcma/core.c
index 63c8b47..03bbe10 100644
--- a/drivers/bcma/core.c
+++ b/drivers/bcma/core.c
@@ -65,7 +65,7 @@
 	switch (clkmode) {
 	case BCMA_CLKMODE_FAST:
 		bcma_set32(core, BCMA_CLKCTLST, BCMA_CLKCTLST_FORCEHT);
-		udelay(64);
+		usleep_range(64, 300);
 		for (i = 0; i < 1500; i++) {
 			if (bcma_read32(core, BCMA_CLKCTLST) &
 			    BCMA_CLKCTLST_HAVEHT) {