fix lbmk shellcheck errors

There was also a condition in run_make_command that is now
an OR, where it was an AND, on script/trees, to fix the use
of mixed (and erroneous) OR/AND operators.

I'm planning a much more invasive audit than this. These are
light fixes, intended for Libreboot 20241206 rev8.

Signed-off-by: Leah Rowe <leah@libreboot.org>

build

@@ -14,7 +14,7 @@ fi
 . "include/vendor.sh"
 . "include/mrc.sh"
 
-eval `setvars "" vdir src_dirname srcdir mode xp ser`
+eval "`setvars "" vdir src_dirname srcdir mode xp ser`"
 err="fail"
 
 main()
@@ -48,7 +48,7 @@ git_init()
 {
 	[ -L ".git" ] && return 1
 	[ -e ".git" ] && return 0
-	eval `setvars "$(date -Rud @$versiondate)" cdate _nogit`
+	eval "`setvars "$(date -Rud @$versiondate)" cdate _nogit`"
 
 	git init || return 1
 	git add -A . || return 1