top: enhanced 'scale_tics' function for Ctrl-E scaling

top: enhanced 'scale_tics' function for Ctrl-E scaling

When scale_tics was refactored and then Ctrl-E support
added to top, the complete range of scaling values was
not visible. Namely, a single 'd' (days) & 'w' (weeks)
was never seen with ^E. With this commit they will be.

Reference(s):
. Mar, 2022 - introduced ^E tics scaling
commit 402bf1903b25ac78b0c4cbf63d457feee78a391c
. Mar, 2022 - refactored scale_tics
commit 71eb90c1b27ef039ccc90f6060406099df45eade

Signed-off-by: Jim Warner <james.warner@comcast.net>