techpack: audio: Fix false positive -Wstrlcpy-strlcat-size

strlen(swr_dmic_name_prefix_of) + 1 bytes are allocated for prefix_name just above

techpack/audio/asoc/codecs/swr-dmic.c:685:11: error: size argument in 'strlcpy' call appears to be size of the source; expected the size of the destination [-Werror,-Wstrlcpy-strlcat-size]
                        strlen(swr_dmic_name_prefix_of) + 1);
                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.

Change-Id: I808b4f135d42fc50587eeb9348848f7e0a3561cc
Signed-off-by: Alexander Winkowski <dereference23@outlook.com>