media-video/mpv: drop unmaintained sparc keywords

Sadly, sparc team appears to be inactive and still struggling with
keyword requests dating back to 2012--2014. Some of these keyword
requests are for security vulnerabilities, e.g. bug 574786.

Rekeyword request for mpv (bug 608316) hasn't seen any action from sparc
team for 3 months. Thus dropping sparc keywords from all mpv ebuilds.

Gentoo-Bug: 608316
Package-Manager: Portage-2.3.5, Repoman-2.3.2

media-video/mpv/mpv-0.18.0-r1.ebuild

@@ -15,7 +15,7 @@ HOMEPAGE="https://mpv.io/"
 
 if [[ ${PV} != *9999* ]]; then
 	SRC_URI="https://github.com/mpv-player/mpv/archive/v${PV}.tar.gz -> ${P}.tar.gz"
-	KEYWORDS="alpha amd64 ~arm hppa ppc ppc64 ~sparc x86 ~amd64-linux"
+	KEYWORDS="alpha amd64 ~arm hppa ppc ppc64 x86 ~amd64-linux"
 	DOCS=( RELEASE_NOTES )
 else
 	EGIT_REPO_URI="git://github.com/mpv-player/mpv.git"

media-video/mpv/mpv-0.22.0-r2.ebuild

@@ -15,7 +15,7 @@ HOMEPAGE="https://mpv.io/"
 
 if [[ ${PV} != *9999* ]]; then
 	SRC_URI="https://github.com/mpv-player/mpv/archive/v${PV}.tar.gz -> ${P}.tar.gz"
-	KEYWORDS="~alpha ~amd64 ~arm ~hppa ~ppc ~ppc64 ~sparc ~x86 ~amd64-linux"
+	KEYWORDS="~alpha ~amd64 ~arm ~hppa ~ppc ~ppc64 ~x86 ~amd64-linux"
 	DOCS=( RELEASE_NOTES )
 else
 	EGIT_REPO_URI=( {https,git}://github.com/mpv-player/mpv.git )