uio: uio_fsl_elbc_gpcm: Make dev_attr_reg_br and dev_attr_reg_or static

Fix sparse warnings:

drivers/uio/uio_fsl_elbc_gpcm.c:71:1: warning:
 symbol 'dev_attr_reg_br' was not declared. Should it be static?
drivers/uio/uio_fsl_elbc_gpcm.c:72:1: warning:
 symbol 'dev_attr_reg_or' was not declared. Should it be static?

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org?>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>