Documentation: mrvl-cn10k-dpi: Fix macro cross-reference syntax

C macro references are erroneously written using :c:macro:: (note the
double colon). This causes the references to be outputted as combination
of verbatim roles and italicized names instead.

Correct the syntax.

Fixes: 5f67eef6dff394 ("misc: mrvl-cn10k-dpi: add Octeon CN10K DPI administrative driver")
Signed-off-by: Bagas Sanjaya <[e-mail]>
Reviewed-by: Randy Dunlap <[e-mail]>
Tested-by: Randy Dunlap <[e-mail]>
Signed-off-by: Jonathan Corbet <[e-mail]>
Message-ID: <[e-mail]>

Documentation/misc-devices/mrvl_cn10k_dpi.rst

···
 Driver IOCTLs
 =============
 
-:c:macro::`DPI_MPS_MRRS_CFG`
+:c:macro:`DPI_MPS_MRRS_CFG`
 ioctl that sets max payload size & max read request size parameters of
 a pem port to which DMA engines are wired.
 
 
-:c:macro::`DPI_ENGINE_CFG`
+:c:macro:`DPI_ENGINE_CFG`
 ioctl that sets DMA engine's fifo sizes & max outstanding load request
 thresholds.