games/scummvm: Update to 2.1.1

Clean-up some stage QA warnings/issues while I'm here:

• Fix pkg-plist issues if the MP3 option is set to off.

• Add "iconv" to USES as scummvm is linked against libiconv.so.

• Also add "--disable-ogg" to VORBIS_CONFIGURE_OFF if the VORBIS option is set to off. Otherwise scummvm is linked against "libogg.so" which is a dependency of the VORBIS option but "libogg.so" is already pulled in via the non-conditional "libtheoradec.so".

Changelog:

https://www.scummvm.org/news/20200131/

PR: 244272
Approved by: maintainer timeout (4+ weeks)
MFH: 2020Q1 (blanket: bug/regression fixes)