platform/x86: dell-smbios: Add pr_fmt definition to driver

pr_fmt provides formatting to be used by the driver when
displaying errors and messages.

Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Reviewed-by: Pali Pohar <pali.rohar@gmail.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>