drm/edid: Fix drm_edid_encode_panel_id() kerneldoc warning

Due to a simple typo (apparently I can't count. It goes 0, 1, 2 and
not 0, 2, 3) we were getting a kernel doc warning that looked like
this:

include/drm/drm_edid.h:530: warning:
  Function parameter or member 'vend_chr_1' not described in 'drm_edid_encode_panel_id'
include/drm/drm_edid.h:530: warning:
  Excess function parameter 'vend_chr_3' description in 'drm_edid_encode_panel_id'

Fix it.

Fixes: 7d1be0a0

 ("drm/edid: Fix EDID quirk compile error on older compilers")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210927074104.1.Ibf22f2a0b75287a5d636c0570c11498648bf61c6@changeid