I would argue no...

Plans existed to drop an A-Bomb on Germany, but the western front ended before the Manhattan project came to fruition.

German Wermacht armies would surrender when outnumbered by allies and their loss was imminent. The Japanese on the other hand were would fight to the last man, leaving few left to surrender (Read: Bushido) as the US Marines experienced in the pacific theatre.

A land invasion of Japan was estimated to cost 1 Million American lives (Fun Fact: All the Purple Hearts given out since WW2 had been minted in preparation of a Japanese Land Invasion), as well as prolong the war, and give Stalin an opportunist to seize some more Japanese land.

All those things factored into the dropping of the A-Bombs, not so much race.