rtc: mcp795: Fix whitespace and indentation.

Fix whitespace and indentation errors and the following
checkpatch warnings:
- line 15: Block comments use a trailing */ on a separate line
- line 256: Line over 80 characters
No code change.

Signed-off-by: Emil Bartczak <emilbart@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>