SSBI: Remove MSM_ prefix from SSBI drivers

Although the SSBI sub is currently only used on MSM SoCs, it is still
a bus in its own right.  Remove this msm_ prefix from the driver and
it's symbols.  Clients can now refer directly to ssbi_write() and
ssbi_read().

Signed-off-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>