buildroot

configs: bump kernel in rpi_defconfig for misc fixes

Fixes in GPIOs, I2C and DMA.

And since the RPi git tree fork has a non-upstream driver
for rtl8192c WiFi USB stick, there's a fix for that, too.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>