scripts: kernel-doc: parse DEFINE_DMA_UNMAP_[ADDR|LEN]

scripts: kernel-doc: parse DEFINE_DMA_UNMAP_[ADDR|LEN]

At present, if the macros DEFINE_DMA_UNMAP_ADDR() and
DEFINE_DMA_UNMAP_LEN() are used in the structures as shown
below, instead of parsing the parameter in the parentheses,
kernel-doc parses 'DEFINE_DMA_UNMAP_ADDR(' and
'DEFINE_DMA_UNMAP_LEN(' which results in the following
warnings:

drivers/net/ethernet/intel/idpf/idpf_txrx.h:201: warning: Function
parameter or member 'DEFINE_DMA_UNMAP_ADDR(dma' not described in
'idpf_tx_buf'
drivers/net/ethernet/intel/idpf/idpf_txrx.h:201: warning: Function
parameter or member 'DEFINE_DMA_UNMAP_LEN(len' not described in
'idpf_tx_buf'

struct idpf_tx_buf {
	DEFINE_DMA_UNMAP_ADDR(dma);
	DEFINE_DMA_UNMAP_LEN(len);
};

Fix the warnings by parsing DEFINE_DMA_UNMAP_ADDR() and
DEFINE_DMA_UNMAP_LEN().

Cc: Jonathan Corbet <corbet@lwn.net>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Pavan Kumar Linga <pavan.kumar.linga@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230815210417.98749-2-pavan.kumar.linga@intel.com