riscv: __asm_copy_to-from_user: Remove unnecessary size check

Clean up:

The size of 0 will be evaluated in the next step. Not
required here.
Signed-off-by: NAkira Tsukamoto <akira.tsukamoto@gmail.com>
Fixes: ca6eaaa2 ("riscv: __asm_copy_to-from_user: Optimize unaligned memory access and pipeline stall")
Signed-off-by: NPalmer Dabbelt <palmerdabbelt@google.com>

arch/riscv/lib/uaccess.S

@@ -30,7 +30,6 @@ ENTRY(__asm_copy_from_user)
 	 * t0 - end of uncopied dst
 	 */
 	add	t0, a0, a2
-	bgtu	a0, t0, 5f
 
 	/*
 	 * Use byte copy only if too small.