dell-smbios: rename dell_send_request() to dell_smbios_send_request()

As dell_send_request() is exported from the module, its prefix should be
consistent with other exported symbols, so change function name to
dell_smbios_send_request().

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>