iwlwifi: iwl-eeprom-parse: mostly dvm only

Most of iwl-eeprom-parse.c is only used for dvm but not for mvm.
Hide the parts under #if IS_ENABLED(CONFIG_IWLDVM) to reduce size
and code surface for mvm-only builds.

Sponsored by:  The FreeBSD Foundation
Signed-off-by: Bjoern A. Zeeb <bz@FreeBSD.ORG>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>