arm64/sme: Manually encode ZT0 load and store instructions

In order to avoid unrealistic toolchain requirements we manually encode the
instructions for loading and storing ZT0.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221208-arm64-sme2-v4-6-f2fa0aef982f@kernel.orgSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/include/asm/fpsimdmacros.h

@@ -220,6 +220,28 @@
 		| ((\offset) & 7)
 .endm
 
+/*
+ * LDR (ZT0)
+ *
+ *	LDR ZT0, nx
+ */
+.macro _ldr_zt nx
+	_check_general_reg \nx
+	.inst	0xe11f8000	\
+		 | (\nx << 5)
+.endm
+
+/*
+ * STR (ZT0)
+ *
+ *	STR ZT0, nx
+ */
+.macro _str_zt nx
+	_check_general_reg \nx
+	.inst	0xe13f8000		\
+		| (\nx << 5)
+.endm
+
 /*
  * Zero the entire ZA array
  *	ZERO ZA