drm/amd/display: Fix typo for variable name

[why]
Word "remainder" was misspelled as "reminder" in
reduceSizeAndFraction method variable.

[how]
Fix the spelling.

Signed-off-by: Vladimir Stempen <vladimir.stempen@amd.com>
Reviewed-by: Alexander Deucher <alexander.deucher@amd.com>
Reviewed-by: Bindu R <Bindu.R@amd.com>
Acked-by: Anson Jacob <Anson.Jacob@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>