ARM: davici_emac: Fix condition for number of phy detects

Fix the condition for number of phys in
davinci_eth_phy_detect() function.
CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT indicates number of
phys. From this commit id dc02bada
davinci emac initilazed one less than the number of phy count.

Signed-off-by: Prabhakar Lad <prabhakar.csengg@gmail.com>
Acked-by: Heiko Schocher <hs@denx.de>