The Mirriam-Webster definition of racism:
"the belief that all members of each race possess characteristics or abilities specific to that race, especially so as to distinguish it as inferior or superior to another race or races.
"prejudice, discrimination, or antagonism directed against someone of a different race based on the belief that one's own race is superior."
There's nothing in the definition of the word that would make "reverse" an applicable adjective. It doesn't specify racism as being directed in any particular direction, so adding "reverse" doesn't make sense and is an invalid use of the English language at best, and semantically harmful at worst because it redefines the word racism (sans qualifiers) to strictly mean white-on-black racism and consequently sneaks in the implication that somehow white-on-black racism is "worse" or "different" than any other kind of racism, and it's not. Viewing races as somehow being "different kinds of people" and treating them differently as a result is the actual problem with racism, not the particulars of the races involved.