smb: client: allow both 'lease' and 'nolease' mount options

smb: client: allow both 'lease' and 'nolease' mount options

Change the nolease mount option from fsparam_flag() to fsparam_flag_no()
so that both 'lease' and 'nolease' are accepted as valid mount options.

Previously, only 'nolease' was recognized. Passing 'lease' would fail
with an unknown parameter error (or be silently ignored with 'sloppy').

With this change:
  - 'nolease' disables lease requests (same behavior as before)
  - 'lease' explicitly enables lease requests

This also renames the enum value from Opt_nolease to Opt_lease and uses
result.negated to set ctx->no_lease, which is the standard pattern used
by other flag_no options in the cifs mount option parser.

Signed-off-by: Rajasi Mandal <rajasimandal@microsoft.com>
Reviewed-by: Meetakshi Setiya <msetiya@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>