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/alim15x3.c b/drivers/ide/pci/alim15x3.c
index f2129d5..f2de00a 100644
--- a/drivers/ide/pci/alim15x3.c
+++ b/drivers/ide/pci/alim15x3.c
@@ -72,7 +72,7 @@
 	int s_time, a_time, c_time;
 	u8 s_clc, a_clc, r_clc;
 	unsigned long flags;
-	int bus_speed = ide_pci_clk ? ide_pci_clk : system_bus_clock();
+	int bus_speed = ide_pci_clk ? ide_pci_clk : 33;
 	int port = hwif->channel ? 0x5c : 0x58;
 	int portFIFO = hwif->channel ? 0x55 : 0x54;
 	u8 cd_dma_fifo = 0;