linuxkpi: i2c: Fix 7bit/8bit addressing

Linux is using 7 bit addressing while FreeBSD uses 8 bit addresses
internally, but i2c(8) uses 7 bit address.
This confused me when originally doing the code and I thought that
0x50 was the 8bit EDID address while it's the 7bit address and since
I did all my testing using this I didn't noticed the problem.

Reported by: avg
PR: 265920 (somewhat)

(cherry picked from commit 319a4bddb0b991377208293283a87946e4b5d055)