ide: remove obsoleted "idebus=" kernel parameter

* Remove obsoleted "idebus=" kernel parameter.

* Remove no longer needed ide_system_bus_speed() and system_bus_clock()
  (together with idebus_parameter and system_bus_speed variables).

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/via82cxxx.c b/drivers/ide/pci/via82cxxx.c
index e8c2570..3ed9728a 100644
--- a/drivers/ide/pci/via82cxxx.c
+++ b/drivers/ide/pci/via82cxxx.c
@@ -340,7 +340,7 @@
 	 * Determine system bus clock.
 	 */
 
-	via_clock = (ide_pci_clk ? ide_pci_clk : system_bus_clock()) * 1000;
+	via_clock = (ide_pci_clk ? ide_pci_clk : 33) * 1000;
 
 	switch (via_clock) {
 		case 33000: via_clock = 33333; break;