Staging: keucr: Move the declaration of variable ErrCode in smilmain.c

This patch moves the declaration of variable ErrCode to file smilmain.c
since this is the only file which uses it. Hence, it also removes extern
declaration from the header file smil.h.

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>