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>

arch/arm/mach-omap2/board-cm-t3517.c

@@ -298,5 +298,5 @@ MACHINE_START(CM_T3517, "Compulab CM-T3517")
 	.init_machine	= cm_t3517_init,
 	.init_late	= am35xx_init_late,
 	.timer		= &omap3_timer,
-	.restart	= omap_prcm_restart,
+	.restart	= omap3xxx_restart,
 MACHINE_END