bpf: remove redeclaration of new_n in bpf_verifier_vlog

This new_n is defined in the start of this function.
Its value is overwritten by `new_n = min(n, log->len_total);`
a couple lines before my change,
rendering the shadow declaration unnecessary.

Signed-off-by: Rafael Passos <rafael@rcpassos.me>
Link: https://lore.kernel.org/r/20240615022641.210320-4-rafael@rcpassos.me


Signed-off-by: Alexei Starovoitov <ast@kernel.org>