[media] xc5000: optimize firmware retry logic

Currently, firmware retry logic keeps reading from FS every
time during the retry logic. This is not needed. Instead,
only release the firmware read after success.

While here, make the non-debug messages less verbose, as it
only matters to the user if the firmware was successfully
loaded, or if some error happened.

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>