powerpc: Stop using no_llseek

Since commit 868941b1 ("fs: remove no_llseek"), no_llseek() is
simply defined to be NULL, and a NULL llseek means seeking is
unsupported.

So for statically defined file_operations, such as all these, there's no
need or benefit to set llseek = no_llseek.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240903111951.141376-1-mpe@ellerman.id.au