nvmem: sunplus-ocotp: staticize sp_otp_v0

The "sp_otp_v0" file scope variable is not used outside, so make it
static to fix warning:

  drivers/nvmem/sunplus-ocotp.c:74:29: sparse:
    sparse: symbol 'sp_otp_v0' was not declared. Should it be static?

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20220321110326.44652-2-krzk@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>