mfd: si476x: Don't use 0bNNN

This doesn't compile with sparc64 gcc-3.4.5.

Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>