nvmem: add missing MODULE_DESCRIPTION() macros

nvmem: add missing MODULE_DESCRIPTION() macros

make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/nvmem/nvmem-apple-efuses.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/nvmem/nvmem_brcm_nvram.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/nvmem/nvmem_u-boot-env.o

Add the missing invocations of the MODULE_DESCRIPTION() macro.

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20240705074852.423202-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>