Staging: sxg: Remove unused Rev A microcode files

Remove the deprecated microcode which was for Rev A.
Now on the driver will use Rev B microcode only.

Signed-off-by: Michael Miles <mmiles@alacritech.com>
Signed-off-by: Mithlesh Thukral <mithlesh@linsyssoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>