nvmem: core: Handle shift bits in-place if cell->nbits is non-zero

It's pointless to test (cell->bit_offset || cell->bit_offset).
nvmem_shift_read_buffer_in_place() should be called when
(cell->bit_offset || cell->nbits).

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>