misc: altera-stapl: drop Kconfig comment

When I2C is enabled, the comment string for "Altera FPGA firmware
download module" adds no new information or value.  It is only useful
and interesting when I2C is not enabled.  In that case, have it
show that I2C is needed for that module.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Igor M. Liplianin <liplianin@netup.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>