arm64/sve: Add some comments for sve_save/load_state()

The use of macros for the actual function bodies means legibility is always
going to be a bit of a challenge, especially while we can't rely on SVE
support in the toolchain, but this helps a little.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210812201143.35578-1-broonie@kernel.orgSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/kernel/entry-fpsimd.S

@@ -33,11 +33,24 @@ SYM_FUNC_END(fpsimd_load_state)
 
 #ifdef CONFIG_ARM64_SVE
 
+/*
+ * Save the SVE state
+ *
+ * x0 - pointer to buffer for state
+ * x1 - pointer to storage for FPSR
+ */
 SYM_FUNC_START(sve_save_state)
 	sve_save 0, x1, 2
 	ret
 SYM_FUNC_END(sve_save_state)
 
+/*
+ * Load the SVE state
+ *
+ * x0 - pointer to buffer for state
+ * x1 - pointer to storage for FPSR
+ * x2 - VQ-1
+ */
 SYM_FUNC_START(sve_load_state)
 	sve_load 0, x1, x2, 3, x4
 	ret