rtc: sparc: make sun4v explicitly non-modular

The Kconfig currently controlling compilation of this code is:

drivers/rtc/Kconfig:config RTC_DRV_SUN4V
drivers/rtc/Kconfig:    bool "SUN4V Hypervisor RTC"

...meaning that it currently is not being built as a module by anyone.

Lets remove the couple traces of modular infrastructure use, so that
when reading the driver there is no doubt it is builtin-only.

We delete the MODULE_LICENSE tag etc. since all that information
was (or is now) contained at the top of the file in the comments.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: rtc-linux@googlegroups.com
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>