[U-Boot] new e1000 compiler warnings

[Kumar Gala]

e1000.c: In function 'e1000_raise_ee_clk':
e1000.c:155:2: warning: unused variable 'x'
e1000.c: In function 'e1000_lower_ee_clk':
e1000.c:172:2: warning: unused variable 'x'
e1000.c: In function 'e1000_shift_out_ee_bits':
e1000.c:208:3: warning: unused variable 'x'
e1000.c: In function 'e1000_standby_eeprom':
e1000.c:279:3: warning: unused variable 'x'
e1000.c:285:3: warning: unused variable 'x'
e1000.c:291:3: warning: unused variable 'x'
e1000.c:297:3: warning: unused variable 'x'
e1000.c:303:3: warning: unused variable 'x'
e1000.c:307:3: warning: unused variable 'x'
e1000.c: In function 'e1000_release_eeprom':
e1000.c:689:3: warning: unused variable 'x'
e1000.c:695:3: warning: unused variable 'x'
e1000.c: In function 'e1000_reset_hw':
e1000.c:1401:2: warning: unused variable 'x'
e1000.c:1428:3: warning: unused variable 'x'
e1000.c: In function 'e1000_init_hw':
e1000.c:1635:3: warning: unused variable 'x'
e1000.c:1647:3: warning: unused variable 'x'
e1000.c:1661:3: warning: unused variable 'x'
e1000.c: In function 'e1000_setup_fiber_link':
e1000.c:2029:2: warning: unused variable 'x'
e1000.c: In function 'e1000_config_collision_dist':
e1000.c:3235:2: warning: unused variable 'x'
e1000.c: In function 'e1000_raise_mdi_clk':
e1000.c:3960:2: warning: unused variable 'x'
e1000.c: In function 'e1000_lower_mdi_clk':
e1000.c:3977:2: warning: unused variable 'x'
e1000.c: In function 'e1000_shift_out_mdi_bits':
e1000.c:4020:3: warning: unused variable 'x'
e1000.c: In function 'e1000_shift_in_mdi_bits':
e1000.c:4059:2: warning: unused variable 'x'
e1000.c: In function 'e1000_phy_hw_reset':
e1000.c:4341:3: warning: unused variable 'x'
e1000.c:4349:3: warning: unused variable 'x'
e1000.c:4362:3: warning: unused variable 'x'
e1000.c:4366:3: warning: unused variable 'x'
e1000.c: In function 'e1000_configure_rx':
e1000.c:4991:3: warning: unused variable 'x'
e1000.c: In function 'e1000_transmit':
e1000.c:5049:2: warning: unused variable 'x'
e1000.c: In function 'e1000_initialize':
e1000.c:869:14: warning: 'checksum' may be used uninitialized in this function