package/micropython: fix license hash

package/micropython: fix license hash

Commit 7676191cfacbdb1a92af1d0218d3280207b03090 forgot to update
license hash which changed due to an update in year:
https://github.com/micropython/micropython/commit/338b12d3c840ea56504c83d9c51e4d0f628684f4

While at it, also update indentation in hash file (two spaces)

Fixes:
 - http://autobuild.buildroot.org/results/2a650636965d8575374333f847acc169caf8d2ac

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>