smaller conf correction in PKGBUILD

uboot-rock64/PKGBUILD

@@ -5,7 +5,7 @@ buildarch=8
 
 pkgname=uboot-rock64
 pkgver=2020.01
-pkgrel=1
+pkgrel=3
 pkgdesc="U-Boot for Rock64"
 arch=('aarch64')
 url='http://www.denx.de/wiki/U-Boot/WebHome'
@@ -18,24 +18,32 @@ source=("ftp://ftp.denx.de/pub/u-boot/u-boot-${pkgver/rc/-rc}.tar.bz2"
         "git+https://github.com/rockchip-linux/rkbin.git#commit=$_commit_rkbin"
         'rk3328trust.ini'
         'boot.txt'
-        'mkscr')
+        'mkscr'
+        'btrfs_extentio.patch')
 md5sums=('b6b2e0787b6874e6b57da0a065a84f5a'
          'SKIP'
          '48946b910716b90d81f47caafb752fef'
-         '3f31f9e58b2f6037fa92998b3323304e'
-         '021623a04afd29ac3f368977140cfbfd')
+         '5f1089c471f39b303bccbb9e1fc196f7'
+         '021623a04afd29ac3f368977140cfbfd'
+         '51ff4b7c8cf8833df2f208fac7fafde5')
+
+prepare() {
+  cd ${srcdir}/u-boot-${pkgver/rc/-rc}/configs
+  echo 'CONFIG_CMD_BTRFS=y' >> rock64-rk3328_defconfig
+  echo 'CONFIG_FS_BTRFS=y' >> rock64-rk3328_defconfig
+  echo 'CONFIG_NETCONSOLE=y' >> rock64-rk3328_defconfig
+  echo 'CONFIG_IDENT_STRING=" Arch Linux ARM"' >> rock64-rk3328_defconfig
+  cd ${srcdir}/u-boot-${pkgver/rc/-rc}/fs/btrfs
+  patch --forward --strip=3 --input="${srcdir}/btrfs_extentio.patch"
+}
 
 build() {
-  cd u-boot-${pkgver/rc/-rc}
+  cd ${srcdir}/u-boot-${pkgver/rc/-rc}
 
   unset CLFAGS CXXFLAGS CPPFLAGS LDFLAGS
 
   make distclean
   make rock64-rk3328_defconfig
-  echo 'CONFIG_CMD_BTRFS=y' >> .config
-  echo 'CONFIG_FS_BTRFS=y' >> .config
-  echo 'CONFIG_NETCONSOLE=y' >> .config
-  echo 'CONFIG_IDENT_STRING=" Arch Linux ARM"' >> .config
   make -j4 EXTRAVERSION=-${pkgrel}
 }