drivers/i2c/rv3028c7: Add ACPI generation callbacks

drivers/i2c/rv3028c7: Add ACPI generation callbacks

Add ACPI generation callback to the driver after obtaining the
ACPI HID "MCRY3028" for this device from Microcrystal AG (VID: "MCRY").

Also add I2C bus speed field to the device config structure, which
is a required ACPI entry.

BUG=none
TEST=Disassemble the SSDT table and see whether the device entry
"MC28" is generated correctly. Also check whether the RV3028 driver
in Linux (drivers/rtc/rtc-rv-3028.c) is bound correctly after adding
an ACPI match table to it containing the HID. A proper kernel patch
is pending.

Change-Id: I3b8cf5c8dc551439755992ff05b6693e91cc3f21
Signed-off-by: Jan Samek <jan.samek@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69543
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>