net/sfc/base: fix signed/unsigned mismatch

[ upstream commit b69259c ]

Use UINT32_MAX instead of assigning -1 to a uint32_t variable to
resolve "conversion from 'int' to 'uint32_t', signed/unsigned mismatch"
errors produced by the Visual Studio 2017 toolchain [with the default
/W4 /WX C compiler options which set warning level 4 and treat warnings
as errors].

Fixes: 107cf1d ("net/sfc/base: move limits config to ef10 NIC board config")

Signed-off-by: Andrew Lee <alee@solarflare.com>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>

drivers/net/sfc/base/ef10_nic.c

@@ -1932,7 +1932,7 @@ ef10_nic_board_cfg(
 	encp->enc_rxq_limit = EFX_RXQ_LIMIT_TARGET;
 	encp->enc_txq_limit = EFX_TXQ_LIMIT_TARGET;
 
-	encp->enc_buftbl_limit = 0xFFFFFFFF;
+	encp->enc_buftbl_limit = UINT32_MAX;
 
 	/* Get interrupt vector limits */
 	if ((rc = efx_mcdi_get_vector_cfg(enp, &base, &nvec, NULL)) != 0) {