eir: Use unsigned int for flags in struct eir_data

eir: Use unsigned int for flags in struct eir_data

This adds assumption that if flags field is not present in EIR all
flags are unset:
"The Flags data type shall be included when any of the Flag bits are
non-zero, otherwise the Flags data type may be omitted."

This also fix reporting non-discoverable LE devices as limited
discoverable due to no explicit check for flags == -1 as empty
flags.