wcnss: remove obsolete define WCNSS_NV_NAME

Remove obsolete define WCNSS_NV_NAME which was originally used to
specify the file from which to obtain the has_48mhz_ xo option.  That
logic was replaced with a board file option with module param
override, but this define was inadvertently not removed at that time.

Change-Id: I810c07115a76e938fded8e6ab92d3ff72d56e6aa
Signed-off-by: Jeff Johnson <jjohnson@codeaurora.org>