media: staging/cxd2099: cosmetics: improve strings

Prefix dev_*() I2C address prints with 0x, change CXD2099 to CXD2099AR,
change the MODULE_DESCRIPTION to a proper one and have a better (and
shorter) description for the buffermode modparam.

Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Jasmin Jessich <jasmin@anw.at>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>