main/dtbtool-sprd: add dtc as a dependency as a fallback (MR 5275)

Currently, dtbtool-sprd has an argument -p which accepts the path to the
dtc binary. When it's not provided, it should use the dtc binary installed
in the system as a fallback. However, that's not the case. The following
error is reported:

Found file: test.dtb ... skip, failed to scan for 'sprd,sc-id = <' tag

...even though test.dtb has the `sprd,sc-id` property.

In order to mitigate such issues, install dtc as a dependency of the
package.

main/dtbtool-sprd/APKBUILD

@@ -1,11 +1,12 @@
 # Maintainer: Anri Dellal <anridellal@gmail.com>
 pkgname=dtbtool-sprd
 pkgver=1.1.2
-pkgrel=0
+pkgrel=1
 pkgdesc="Tool for compiling a dtb.img for Spreadtrum SoC"
 url="https://gitlab.com/Grimler/dtbtool-sprd"
 arch="all"
 license="MIT"
+depends="dtc"
 makedepends="dtc-dev"
 options="!check" # There is no testsuite
 source="