power: qpnp-smbcharger: fix USBID ADC code reading

Currently, the USBID reading is assuming the PMI8994 USBID ADC code byte
ordering is the same as the architecture. This is not correct and can
cause certain OTG cables to be wrongly detected as non-OTG and
vice-versa.

Fix the byte ordering so that the correct USBID is being read.

Change-Id: Icd3c0cf3e522f2beef5e6ba8e900118e47380b8a
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>