pinctrl-8996: remove inapplicable copyright

The GPLv2 copyright statement includes an attribution
to Sony which was accidentally copied from another file.
Since the 8996 pinctrl driver does not leverage code
from sources besides the Linux Foundation,
clean-up the copyright text accordingly.

Change-Id: I324088aea2abde4fe34769a63d4ab55b35e13b81
Signed-off-by: Sanrio Alvares <salvares@codeaurora.org>