pcpskr: MIPS: Make config dependencies finer grained

Only the Siemens-Nixdorf RM series workstations and the Jazz family
workstations have PC speakers built in; Malta can connect one via the
infamous AMR connector with an AMR sound card or a little creativity.
So we don't want to offer the PC speaker driver on all MIPS systems.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Link: http://lkml.kernel.org/r/20110601180611.061710714@duck.linux-mips.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>