The current strtoll() implementation in hvmloader requires hex number to be
prefixed with 0x, otherwise strtoll() won't parse them correctly even when
calling the function with base == 16.
Fix this by not unconditionally setting the base to 10 when the string is
not 0 prefixed, this also allows parsing octal numbers not 0 prefixed.
While there also handle '0X' as a valid hex number prefix, together with
'0x'.
No functional change intended to the existing call sites.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>