Staging: bcm: nvm.c: Outsourced chunk of code into function

This patch outsources a chunk of code into an own function. It also
refactors the variable names which are used within this function.

The function name may be not appropriate.

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>