Staging: bcm: Remove typedef for _NVM_READWRITE and call directly.

This patch removes typedef for _NVM_READWRITE,
and changes the name of the struct to
bcm_nvm_readwrite. In addition, any calls to
typedefs NVM_READWRITE, or *PNVM_READWRITE
are changed to call the struct directly.

Signed-off-by: Kevin McKinney <klmckinney1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>