rtc: ds1307: remove regs member

ds1307->regs is never used before being read or initialized locally. There
is no point in keeping a copy in memory.

Also limit the size of the read buffer to what is really used, rename buf
to regs for consistency and use sizeof() where possible.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
1 file changed