Remove unnecessary includes of primecell.h

The primecell.h header now only has the definitions of constants
indicating the usage of the arm_sysctl GPIO lines; remove obsolete
includes of it from source files which don't care about those GPIO
lines.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/highbank.c

@@ -19,7 +19,6 @@
 
 #include "sysbus.h"
 #include "arm-misc.h"
-#include "primecell.h"
 #include "devices.h"
 #include "loader.h"
 #include "net.h"

hw/integratorcp.c

@@ -8,7 +8,6 @@
  */
 
 #include "sysbus.h"
-#include "primecell.h"
 #include "devices.h"
 #include "boards.h"
 #include "arm-misc.h"

hw/pl022.c

@@ -9,7 +9,6 @@
 
 #include "sysbus.h"
 #include "ssi.h"
-#include "primecell.h"
 
 //#define DEBUG_PL022 1
 

hw/versatilepb.c

@@ -9,7 +9,6 @@
 
 #include "sysbus.h"
 #include "arm-misc.h"
-#include "primecell.h"
 #include "devices.h"
 #include "net.h"
 #include "sysemu.h"