nvmem: remove inline in drivers/nvmem/core.c

These two functions are defined in .c file, but called just once
(at least for now).  So, the compiler will fold them into their
callers even without the "inline" markers.

However, this kind of optimization should not be done by hand.
It is compiler's judge after all.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>