If I were your employer, I would definitely consider firing you because I do not believe my company should employ people who are tolerant of racism, sexism, xenophobia, homophobia and political violence.
It's the same reason I would fire any employee who are openly in support of KKK or Nazi. Some people may argue that they disagree with Donald Trump on those things but support his policies. That's like saying it's ok for me to support Hitler because his economic recovery plan for Germany is sound, but I just disagree with the whole genocide business.
EDIT: I do believe in the First Amendment. As long as they don't violate Federal laws regarding hate speech to incite violence, Mr.Trump and his supporters should be allowed to exercise their free speech without fear of government prosecution.
However I am also for the right of any private party to distance and disassociate themselves from Mr.Trump and his supporters, including their employers.