Revert "net: netcp: MAX_SKB_FRAGS is now 'int'"

This reverts commit c5b959ee.

Reverted change is required after commit 3948b059 ("net: introduce
a config option to tweak MAX_SKB_FRAGS") which does not exist
in this tree, yet. It's only present in -next trees at the time
of writing.

Reported-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/all/20230331214444.GA1426512@dev-arch.thelio-3990X/


Signed-off-by: Jakub Kicinski <kuba@kernel.org>