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-ti8168evm.c b/arch/arm/mach-omap2/board-ti8168evm.c
index 5e672c2..1a3e056 100644
--- a/arch/arm/mach-omap2/board-ti8168evm.c
+++ b/arch/arm/mach-omap2/board-ti8168evm.c
@@ -46,7 +46,7 @@
 	.timer		= &omap3_timer,
 	.init_machine	= ti81xx_evm_init,
 	.init_late	= ti81xx_init_late,
-	.restart	= omap_prcm_restart,
+	.restart	= omap44xx_restart,
 MACHINE_END
 
 MACHINE_START(TI8148EVM, "ti8148evm")
@@ -58,5 +58,5 @@
 	.timer		= &omap3_timer,
 	.init_machine	= ti81xx_evm_init,
 	.init_late	= ti81xx_init_late,
-	.restart	= omap_prcm_restart,
+	.restart	= omap44xx_restart,
 MACHINE_END