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/cy82c693.c b/drivers/ide/pci/cy82c693.c
index 77cc22c..8c534af 100644
--- a/drivers/ide/pci/cy82c693.c
+++ b/drivers/ide/pci/cy82c693.c
@@ -134,7 +134,7 @@
 static void compute_clocks(u8 pio, pio_clocks_t *p_pclk)
 {
 	int clk1, clk2;
-	int bus_speed = ide_pci_clk ? ide_pci_clk : system_bus_clock();
+	int bus_speed = ide_pci_clk ? ide_pci_clk : 33;
 
 	/* we don't check against CY82C693's min and max speed,
 	 * so you can play with the idebus=xx parameter