Fix register docs

src/register/vdci.rs

@@ -1,4 +1,4 @@
-//! uscratch register
+//! DCache Information register
 
 read_csr_as_usize!(0xCC0, __read_vdci);
 write_csr_as_usize!(0xCC0, __write_vdci);

src/register/vmim.rs

@@ -1,4 +1,4 @@
-//! uscratch register
+//! Machine IRQ Mask register
 
 read_csr_as_usize!(0xBC0, __read_vmim);
 write_csr_as_usize!(0xBC0, __write_vmim);

src/register/vmip.rs

@@ -1,4 +1,4 @@
-//! uscratch register
+//! Machine IRQ Pending register
 
 read_csr_as_usize!(0xFC0, __read_vmip);
 write_csr_as_usize!(0xFC0, __write_vmip);

src/register/vsim.rs

@@ -1,4 +1,4 @@
-//! uscratch register
+//! Supervisor IRQ Mask register
 
 read_csr_as_usize!(0x9C0, __read_vsim);
 write_csr_as_usize!(0x9C0, __write_vsim);

src/register/vsip.rs

@@ -1,4 +1,4 @@
-//! uscratch register
+//! Supervisor IRQ Pending register
 
 read_csr_as_usize!(0xDC0, __read_vsip);
 write_csr_as_usize!(0xDC0, __write_vsip);