fsl-rio: fix compile error

The "#include <linux/module.h>" was replaced by "#include <linux/export.h>"
in the patch "powerpc: various straight conversions from module.h --> export.h".
This will cause the following compile problem:
arch/powerpc/sysdev/fsl_rio.c: In function 'fsl_rio_mcheck_exception':
arch/powerpc/sysdev/fsl_rio.c:296: error: implicit declaration of function 'search_exception_tables'.

The file fsl_rio.c needs the declaration of function "search_exception_tables"
in the header file "linux/module.h".

Signed-off-by: Liu Gang <Gang.Liu@freescale.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>