roms/edk2-funcs.sh: require gcc-4.8+ for building i386 and x86_64

Adapt the qemu_edk2_get_toolchain() function in "roms/edk2-funcs.sh" in
advance to edk2 commit 8d7cdfae8cb8 ("OvmfPkg: require GCC48 or later",
2019-01-08), which is part of the "edk2-stable201903" tag.

Signed-off-by: Laszlo Ersek <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Tested-by: Philippe Mathieu-Daudé <[email protected]>
Reviewed-by: Michal Privoznik <[email protected]>
Reviewed-by: Michael S. Tsirkin <[email protected]>
Tested-by: Igor Mammedov <[email protected]>
Reviewed-by: Igor Mammedov <[email protected]>

roms/edk2-funcs.sh

@@ -149,23 +149,11 @@ qemu_edk2_get_toolchain()
       # Run "git-blame" on "OvmfPkg/build.sh" in edk2 for more information on
       # the mapping below.
       case "$gcc_version" in
-        ([1-3].*|4.[0-3].*)
+        ([1-3].*|4.[0-7].*)
           printf '%s: unsupported gcc version "%s"\n' \
             "$program_name" "$gcc_version" >&2
           return 1
           ;;
-        (4.4.*)
-          printf 'GCC44\n'
-          ;;
-        (4.5.*)
-          printf 'GCC45\n'
-          ;;
-        (4.6.*)
-          printf 'GCC46\n'
-          ;;
-        (4.7.*)
-          printf 'GCC47\n'
-          ;;
         (4.8.*)
           printf 'GCC48\n'
           ;;