omap3evm: fix errors caused by multiple definitions

Fix these errors when building with recently added
omap3_evm_quick_nand_config:

env_nowhere.o: In function `env_relocate_spec':
/home/premi/u-boot/common/env_nowhere.c:40: multiple definition
 of `env_relocate_spec'
env_nand.o:/home/premi/u-boot/common/env_nand.c:416: first defi
ned here
env_nowhere.o: In function `env_get_char_spec':
/home/premi/u-boot/common/env_nowhere.c:44: multiple definition
 of `env_get_char_spec'
env_nand.o:/home/premi/u-boot/common/env_nand.c:77: first defin
ed here
env_nowhere.o: In function `env_init':
/home/premi/u-boot/common/env_nowhere.c:54: multiple definition
 of `env_init'
env_nand.o:/home/premi/u-boot/common/env_nand.c:144: first defi
ned here
env_nowhere.o: In function `env_relocate_spec':
/home/premi/u-boot/common/env_nowhere.c:40: multiple definition
 of `env_ptr'
env_nand.o:/home/premi/u-boot/common/env_nand.c:77: first defin
ed here

Signed-off-by: Sanjeev Premi <premi@ti.com>
Cc: Sandeep Paulraj <s-paulraj@ti.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>