When performing floating point multiplication, the prior code overwrote
an additional word of the floating point fraction with zeros. This is
harmless with standard FP, as the floating variables always have space
for EP-length vars. When doing an EP multiply, this causes a word on
the stack to be zeroed. For the latest Raspbian release, this causes a
segfault as there's no padding past that var on the stack.
This fix, which has been tested against the original crashing code plus
validated using the FPP-8 diagnostics, avoids the overwrite.
030a47bdb4