nvmem: core: switch to use device_add_groups()

nvmem: core: switch to use device_add_groups()

devm_device_add_groups() is being removed from the kernel, so move the
nvmem driver to use device_add_groups() instead.  The logic is
identical, when the device is removed the driver core will properly
clean up and remove the groups, and the memory used by the attribute
groups will be freed because it was created with dev_* calls, so this is
functionally identical overall.

Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20240430084921.33387-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>