genksyms: rename cvar_qualifier to type_qualifier

I believe "cvar" stands for "Const, Volatile, Attribute, or Restrict".

This is called "type-qualifier" in K&R. [1]

Adopt this more generic naming.

No functional changes are intended.

[1] https://cs.wmich.edu/~gupta/teaching/cs4850/sumII06/The%20syntax%20of%20C%20in%20Backus-Naur%20form.htm



Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Nicolas Schier <n.schier@avm.de>