staging: r8188eu: Fix cast between incompatible function type

staging: r8188eu: Fix cast between incompatible function type

Fix sparse warnings of casts between incompatible function
types from ‘void (*)(void *)’ to ‘void (*)(long unsigned int)’
[-Wcast-function-type].

Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Link: https://lore.kernel.org/r/20210804143218.13665-1-fmdefrancesco@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>