CLEANUP: proxy_protocol: Use `size_t` when parsing TLVs

Change `int` to `size_t` for consistency.
diff --git a/src/connection.c b/src/connection.c
index 1ea8e9f..4e3a92f 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -457,7 +457,7 @@
 /*
  * Get data length from tlv
  */
-static int get_tlv_length(const struct tlv *src)
+static inline size_t get_tlv_length(const struct tlv *src)
 {
 	return (src->length_hi << 8) | src->length_lo;
 }
@@ -491,7 +491,7 @@
 	struct proxy_hdr_v2 *hdr_v2;
 	const char v2sig[] = PP2_SIGNATURE;
 	size_t total_v2_len;
-	int tlv_offset = 0;
+	size_t tlv_offset = 0;
 	int ret;
 
 	if (!conn_ctrl_ready(conn))
@@ -706,7 +706,7 @@
 		/* TLV parsing */
 		while (tlv_offset < total_v2_len) {
 			struct tlv *tlv_packet;
-			int tlv_len;
+			size_t tlv_len;
 
 			/* Verify that we have at least TLV_HEADER_SIZE bytes left */
 			if (tlv_offset + TLV_HEADER_SIZE > total_v2_len)