sifiveu: drop upstreamed patch from 6.12

The gpio-poweroff support has been upstreamed earlier.

Signed-off-by: Zoltan HERPAI <wigyori@uid0.hu>

target/linux/sifiveu/patches-6.12/0004-riscv-sifive-unmatched-add-gpio-poweroff-node.patch

@@ -1,26 +0,0 @@
-From 14ede57943bc4209755d08daf93ac7be967d7fbe Mon Sep 17 00:00:00 2001
-From: David Abdurachmanov <david.abdurachmanov@sifive.com>
-Date: Mon, 13 Sep 2021 02:18:30 -0700
-Subject: [PATCH 4/7] riscv: sifive: unmatched: add gpio-poweroff node
-
-Add gpio-poweroff node to allow powering off the system.
-
-Signed-off-by: David Abdurachmanov <david.abdurachmanov@sifive.com>
----
- arch/riscv/boot/dts/sifive/hifive-unmatched-a00.dts | 6 ++++++
- 1 file changed, 6 insertions(+)
-
---- a/arch/riscv/boot/dts/sifive/hifive-unmatched-a00.dts
-+++ b/arch/riscv/boot/dts/sifive/hifive-unmatched-a00.dts
-@@ -86,6 +86,11 @@
- 			};
- 		};
- 	};
-+
-+	gpio-poweroff {
-+		compatible = "gpio-poweroff";
-+		gpios = <&gpio 2 GPIO_ACTIVE_LOW>;
-+	};
- };
- 
- &uart0 {