riscv: sbi: Remove sbi_spec_version

U-Boot defaults to use SBI v0.2. Howerver there is a global variable
sbi_spec_version that stills refers to v0.1. Since it is not used
anywhere, let's remove it.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Rick Chen <rick@andestech.com>
diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index 453cb5c..08e1ac0 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -77,7 +77,6 @@
 #define SBI_FID_REMOTE_SFENCE_VMA_ASID	SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID
 #endif
 
-#define SBI_SPEC_VERSION_DEFAULT	0x1
 #define SBI_SPEC_VERSION_MAJOR_SHIFT	24
 #define SBI_SPEC_VERSION_MAJOR_MASK	0x7f
 #define SBI_SPEC_VERSION_MINOR_MASK	0xffffff
@@ -90,7 +89,6 @@
 #define SBI_ERR_DENIED			-4
 #define SBI_ERR_INVALID_ADDRESS		-5
 
-extern unsigned long sbi_spec_version;
 struct sbiret {
 	long error;
 	long value;
diff --git a/arch/riscv/lib/sbi.c b/arch/riscv/lib/sbi.c
index 993597e..f298846 100644
--- a/arch/riscv/lib/sbi.c
+++ b/arch/riscv/lib/sbi.c
@@ -11,9 +11,6 @@
 #include <asm/encoding.h>
 #include <asm/sbi.h>
 
-/* default SBI version is 0.1 */
-unsigned long sbi_spec_version = SBI_SPEC_VERSION_DEFAULT;
-
 struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
 			unsigned long arg1, unsigned long arg2,
 			unsigned long arg3, unsigned long arg4,