net: Kconfig NET_DEVMEM selects GENERIC_ALLOCATOR

GENERIC_ALLOCATOR is a non-prompt kconfig, meaning users can't enable it
selectively. All kconfig users of GENERIC_ALLOCATOR select it, except of
NET_DEVMEM which only depends on it, there is no easy way to turn
GENERIC_ALLOCATOR on unless we select other unnecessary configs that
will select it.

Instead of depending on it, select it when NET_DEVMEM is enabled.

Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Mina Almasry <almasrymina@google.com>
Link: https://patch.msgid.link/1747950086-1246773-2-git-send-email-tariqt@nvidia.com


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