staging: bcm2835: cleanup: remove deprecated <asm/uaccess.h> include

This replaces the last occurrence of the deprecated <asm/uaccess.h> include
in the staging directory with the newer <linux/uaccess.h>

Signed-off-by: Seraphime Kirkovski <kirkseraph@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>