fix to check presence of smbios file before read

Issue: Response of read SMBIOS data ipmi command giving hardcoded values
when smbios file doesnt exists.
Fix: Added checks before reading SMBIOS file to ensure the
presence of the file. Absence of the file handles the case
of returning without displaying hardcoded data.
Test Results:
Verified using IPMI command
Command:  ipmitool  raw 0x3E 0x31 0x01 0x01 0x00 //read smbios data
Response:  Unable to send RAW command
(channel=0x0 netfn=0x3e lun=0x0 cmd=0x31 rsp=0xce):Command response
could not be provided.

Signed-off-by: Prithvi A Pai <prithvi.a.pai@intel.com>
Change-Id: I612f71f2ce5bc81fe39b59c6fe742b1d5126dce8
1 file changed