power: smb1360: Support to configure FG registers

The SMB1360 fuel gauge registers are spread across multiple
I2C peripherals.

1. FG Constants and OTP backup	(fg_access_type = 1)
2. FG Battery Profile A		(fg_access_type = 2)
3. FG Battery Profile B		(fg_access_type = 3)

To access the registers across these peripherals
1. Set the FG access type (echo 0x1 > fg_access_type)
2. Set the address to read/write (echo 0x0C > fg_address)
3. Read/Write to the register (cat data / echo 0xA > data)

CRs-Fixed: 679696
Change-Id: I946603639d3c7214fd729ff85f657c59f0c1369f
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>