hpet: common ACPI generation

HPET's min ticks (minimum time between events to avoid
losing interrupts) is chipset specific, so move it to
Kconfig.

Via also has a special base address, so move it as well.

Apart from these (and the base address was already #defined),
the table is very uniform.

Change-Id: I848a2e2b0b16021c7ee5ba99097fa6a5886c3286
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/1562
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Dave Frodin <dave.frodin@se-eng.com>

src/southbridge/amd/sb600/Kconfig

@@ -59,4 +59,8 @@ config SATA_MODE
 	default 1 if SATA_MODE_IDE
 	default 0 if SATA_MODE_AHCI
 
+config HPET_MIN_TICKS
+        hex
+        default 0x14
+
 endif