staging: goldfish: Fix pointer cast for 32 bits

As the first argument of gf_write64() was of type unsigned long, and as
some calls to gf_write64() were casting the first argument from void *
to u64 the compiler and/or sparse were printing warnings for casts of
wrong sizes when compiling for i386.

This patch changes the type of the first argument of gf_write64() to
const void *, and update calls to the function. This change fixed the
warnings and allowed to remove casts from 3 calls to gf_write64().

In addition gf_write64() was renamed to gf_write_ptr() as the name was
misleading because it only writes 32 bits on 32 bit systems.

gf_write_dma_addr() was added to handle dma_addr_t values which is
used at drivers/staging/goldfish/goldfish_audio.c.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>