[ATM]: Make atm/he.c:read_prom_byte() static

This patch makes the needlessly global read_prom_byte() static.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/atm/he.c

@@ -3000,8 +3000,7 @@ he_proc_read(struct atm_dev *dev, loff_t *pos, char *page)
 
 /* eeprom routines  -- see 4.7 */
 
-u8
-read_prom_byte(struct he_dev *he_dev, int addr)
+static u8 read_prom_byte(struct he_dev *he_dev, int addr)
 {
 	u32 val = 0, tmp_read = 0;
 	int i, j = 0;