drm/edid: Add drm_edid_get_monitor_name()

drm/edid: Add drm_edid_get_monitor_name()

In order to include monitor name information in debugfs
output we needed to add a function that would extract the
monitor name from the EDID, and that function needed to
reside in the file  where the rest of the EDID helper
functions are implemented.

v2: Refactor to have drm_edid_get_monitor_name() and drm_edid_to_eld()
    use a common helper function to extract the monitor name from the
    edid. [Jani] + rebase.

v3: Minor changes suggested by Jani + rebase.

v4: Few more minor changes suggested by Jani + rebase.

cc: dri-devel@lists.freedesktop.org
cc: Jani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jim Bride <jim.bride@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1460654317-31288-1-git-send-email-jim.bride@linux.intel.com