ARM: OMAP2+: board files: use SoC-specific system restart functions

Modify the board files to use the SoC-specific system restart
functions.  At this point it's possible to remove omap_prcm_restart()
from mach-omap2/prcm.c.

While removing the prototypes for the now-unused restart functions, clean
up a few more obsolete prototypes in mach-omap2/clock.h.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Tested-by: Vaibhav Hiremath <hvaibhav@ti.com>
diff --git a/arch/arm/mach-omap2/board-n8x0.c b/arch/arm/mach-omap2/board-n8x0.c
index e3efcb8..a4e167c 100644
--- a/arch/arm/mach-omap2/board-n8x0.c
+++ b/arch/arm/mach-omap2/board-n8x0.c
@@ -690,7 +690,7 @@
 	.init_machine	= n8x0_init_machine,
 	.init_late	= omap2420_init_late,
 	.timer		= &omap2_timer,
-	.restart	= omap_prcm_restart,
+	.restart	= omap2xxx_restart,
 MACHINE_END
 
 MACHINE_START(NOKIA_N810, "Nokia N810")
@@ -703,7 +703,7 @@
 	.init_machine	= n8x0_init_machine,
 	.init_late	= omap2420_init_late,
 	.timer		= &omap2_timer,
-	.restart	= omap_prcm_restart,
+	.restart	= omap2xxx_restart,
 MACHINE_END
 
 MACHINE_START(NOKIA_N810_WIMAX, "Nokia N810 WiMAX")
@@ -716,5 +716,5 @@
 	.init_machine	= n8x0_init_machine,
 	.init_late	= omap2420_init_late,
 	.timer		= &omap2_timer,
-	.restart	= omap_prcm_restart,
+	.restart	= omap2xxx_restart,
 MACHINE_END