drivers/net/smc91111.c: fix warning: variable ... set but not used

Fix:
smc91111.c: In function 'smc_phy_configure':
smc91111.c:1194:6: warning: variable 'failed' set but not used [-Wunused-but-set-variable]
smc91111.c:1190:7: warning: variable 'phyaddr' set but not used [-Wunused-but-set-variable]

Signed-off-by: Wolfgang Denk <wd@denx.de>