pipes: Fix readwrite verification function for fp64 (#1522)
pipes: Fix readwrite verification function for fp64 (#1522)

Use the appropriate function for verifying double precision values in
the `pipe_readwrite_double` test.

Change `verify_readwrite_double` to use `cl_long`, as `long long int`
could be wider than 64 bits which would cause out-of-bound reads.
This leaves no functional differences between
`verify_readwrite_double` and `verify_readwrite_long`.

Found by compiling with `-Wunused-function`, which flagged
`verify_readwrite_double` as unused.

Signed-off-by: Sven van Haastregt <c87899f97800fb9ac456b806e5f84934b5e9c197@arm.com>

Signed-off-by: Sven van Haastregt <c87899f97800fb9ac456b806e5f84934b5e9c197@arm.com>
KhronosGroup/OpenCL-CTS,KhronosGroup/OpenCL-CTS,KhronosGroup/OpenCL-CTS,KhronosGroup/OpenCL-CTS