undefined reference to `omap_mbox_register'

HI All,

While working wih TI-SDK Linux for AM335x, many times we get error in kernel buid as

"board-support/linux-3.12.10-ti2013.12.01/drivers/mailbox/mailbox-omap2.c:501: undefined reference to `omap_mbox_register'
make: *** [vmlinux] Error 1"   after step

CC init/version.o
LD init/built-in.o
drivers/built-in.o: In function `omap2_mbox_remove':.

What is the cause of this problem?

to check the path for arm-linux-gnueabihf-gcc, after exporting the path, i test it with "arm-linux-gnueabihf-gcc -v", echo $PATH, which gcc. even after proper answers, if i do distclean>>menuconfig the uImage command fails at above step.

But Def-config works ok, what shoud be the error?

Thanks in advance