flashrom: avoid download URL redirect

flashrom: avoid download URL redirect

Use the https URL to avoid HTTP 308 redirect. Older wget releases treat
it as a hard error.

Fixes:
http://autobuild.buildroot.net/results/ee6/ee66e5ead70e73f1d2dae1c5ba31ccf054fe15a7/
http://autobuild.buildroot.net/results/fb8/fb8509bf9cf03933e45355fd9a6c3fa53d33c44f/
http://autobuild.buildroot.net/results/0e1/0e196570207e459c3440d50cecf0032eee6edfc2/

Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>