riscv: Use run-time endianess for floating point literals

gas/
	PR binutils/30551
	* config/tc-riscv.c (md_atof): Use target_big_endian instead of
	TARGET_BYTES_BIG_ENDIAN.
	* testsuite/gas/riscv/float-be.d: New file.
	* testsuite/gas/riscv/float-le.d: New file.
	* testsuite/gas/riscv/float.s: New file.

gas/config/tc-riscv.c

@@ -3693,7 +3693,7 @@ md_assemble (char *str)
 const char *
 md_atof (int type, char *litP, int *sizeP)
 {
-  return ieee_md_atof (type, litP, sizeP, TARGET_BYTES_BIG_ENDIAN);
+  return ieee_md_atof (type, litP, sizeP, target_big_endian);
 }
 
 void

gas/testsuite/gas/riscv/float-be.d

@@ -0,0 +1,8 @@
+# source: float.s
+# objdump: -sj .data
+# as: -mbig-endian
+
+.*:[ 	]+file format .*bigriscv
+
+Contents of section \.data:
+ 0000 3f8ccccd 40019999 9999999a.*

gas/testsuite/gas/riscv/float-le.d

@@ -0,0 +1,8 @@
+# source: float.s
+# objdump: -sj .data
+# as: -mlittle-endian
+
+.*:[ 	]+file format .*littleriscv
+
+Contents of section \.data:
+ 0000 cdcc8c3f 9a999999 99990140.*

gas/testsuite/gas/riscv/float.s

@@ -0,0 +1,3 @@
+	.data
+	.float	1.1
+	.double	2.2