rv/rvgen: fix PEP 8 whitespace violations

rv/rvgen: fix PEP 8 whitespace violations

Fix whitespace violations throughout the rvgen codebase to comply
with PEP 8 style guidelines. The changes address missing whitespace
after commas, around operators, and in collection literals that
were flagged by pycodestyle.

The fixes include adding whitespace after commas in string replace
chains and function arguments, adding whitespace around arithmetic
operators, removing extra whitespace in list comprehensions, and
fixing dictionary literal spacing. These changes improve code
readability and consistency with Python coding standards.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260223162407.147003-9-wander@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>