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/intel/i82801gx/i82801gx.h

@@ -32,7 +32,6 @@
 #define DEFAULT_GPIOBASE	0x0480
 #define DEFAULT_PMBASE		0x0500
 
-#define HPET_ADDR		0xfed00000
 #define DEFAULT_RCBA		0xfed1c000
 
 #ifndef __ACPI__