topology: plugins: fix off by 1 mem allocation error

[yongzhi1]

Fix valgrind memcheck error:

==1337389== Invalid write of size 1 ==1337389== at 0x4A4AFAB: __vsnprintf_internal (vsnprintf.c:117) ==1337389== by 0x4AECF40: __snprintf_chk (snprintf_chk.c:38) ==1337389== by 0x484B870: snprintf (stdio2.h:67) ==1337389== by 0x484B870: print_as_hex_bytes (nhlt-processor.c:112) ==1337389== by 0x484B870: merge_manifest_data (nhlt-processor.c:154) ==1337389== by 0x484B870: do_nhlt (nhlt-processor.c:420) ==1337389== by 0x484B870: _snd_topology_nhlt_process (nhlt-processor.c:484)

The consecutive snprintf overwrites always the previous terminator until it hits the very last call of:

snprintf(dst, ALSA_BYTE_CHARS + 1, "0x%02x,", *nhlt_buffer);

when the size n given to snprintf is 1 more than allocated.

Signed-off-by: Yong Zhi [email protected]