gnome-shell: Mark incompatible with riscv32

It depends on glycin, which is not available on riscv32, as it
requires libseccomp, which is not ported to rv32.

AI-Generated: Uses Claude Code
Signed-off-by: Khem Raj <khem.raj@oss.qualcomm.com>

meta-gnome/recipes-gnome/gnome-shell/gnome-shell_51.1.bb

@@ -102,3 +102,5 @@ FILES:${PN}-tools = "${bindir}/*-tool"
 RDEPENDS:${PN}-tools = "python3-core"
 
 CVE_STATUS[CVE-2021-3982] = "not-applicable-config: OE doesn't set CAP_SYS_NICE capability"
+
+COMPATIBLE_HOST:riscv32 = "null"