net/ibm/emac: wrong emac_calc_base call was used by typo

__emac_calc_base_mr1 was used instead of __emac4_calc_base_mr1
by copy-paste mistake for emac4syn.

Fixes: 45d6e545 ("net/ibm/emac: add 8192 rx/tx fifo size")
Signed-off-by: Ivan Mikhaylov <ivan@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>