ebefe435d4d7 drm/i915/display: define and use intel_reg_{offset, equal, valid}() helpers
66fb32cd35f2 drm/i915/display: add struct intel_error_regs and use it
05a934f650dc drm/i915/display: add struct intel_irq_regs and use it
f6a16503d05b drm/i915/display: add typedef for intel_reg_t and use it