net: enetc: correct the value of ENETC_RXB_TRUESIZE

ENETC_RXB_TRUESIZE indicates the size of half a page, but the page size
is adjustable, for ARM64 platform, the PAGE_SIZE can be 4K, 16K and 64K,
so a fixed value '2048' is not correct when the PAGE_SIZE is 16K or 64K.

Fixes: d4fd040 ("enetc: Introduce basic PF and VF ENETC ethernet drivers")
Signed-off-by: Wei Fang <wei.fang@nxp.com>
Signed-off-by: NipaLocal <nipa@local>

Author: Wei Fang

drivers/net/ethernet/freescale/enetc/enetc.h

@@ -76,7 +76,7 @@ struct enetc_lso_t {
 #define ENETC_LSO_MAX_DATA_LEN		SZ_256K
 
 #define ENETC_RX_MAXFRM_SIZE	ENETC_MAC_MAXFRM_SIZE
-#define ENETC_RXB_TRUESIZE	2048 /* PAGE_SIZE >> 1 */
+#define ENETC_RXB_TRUESIZE	(PAGE_SIZE >> 1)
 #define ENETC_RXB_PAD		NET_SKB_PAD /* add extra space if needed */
 #define ENETC_RXB_DMA_SIZE	\
 	(SKB_WITH_OVERHEAD(ENETC_RXB_TRUESIZE) - ENETC_RXB_PAD)