machine/stm32: add STM32U585 target definition and runtime

Add processor target (cortex-m33), linker script (2048K flash, 768K RAM),
and arduino-uno-q board target. Runtime initializes 160MHz clock via PLL1
from HSI16, with PWR Range 1 and EPOD booster.

Also add psctype abstraction for timer PSC register width, needed because
the U5 SVD defines PSC as a 16-bit register.

src/machine/machine_stm32_tim.go

@@ -150,7 +150,7 @@ func (t *TIM) setPeriod(period uint64, updatePrescaler bool) error {
 		psc = ceil(top, ARR_MAX)
 		top = top / psc
 
-		t.Device.PSC.Set(uint32(psc - 1))
+		t.Device.PSC.Set(psctype(psc - 1))
 	} else {
 		psc = uint64(t.Device.PSC.Get()) + 1
 		top = top / psc

src/machine/machine_stm32f103.go

@@ -731,6 +731,7 @@ func (t *TIM) enableMainOutput() {
 }
 
 type arrtype = uint32
+type psctype = uint32
 type arrRegType = volatile.Register32
 
 const (

src/machine/machine_stm32f4.go

@@ -607,6 +607,7 @@ func (t *TIM) enableMainOutput() {
 }
 
 type arrtype = uint32
+type psctype = uint32
 type arrRegType = volatile.Register32
 
 const (

src/machine/machine_stm32f7.go

@@ -712,6 +712,7 @@ func (t *TIM) enableMainOutput() {
 }
 
 type arrtype = uint32
+type psctype = uint32
 type arrRegType = volatile.Register32
 
 const (

src/machine/machine_stm32g0.go

@@ -554,6 +554,7 @@ func (t *TIM) enableMainOutput() {
 }
 
 type arrtype = uint32
+type psctype = uint32
 type arrRegType = volatile.Register32
 
 const (

src/machine/machine_stm32l0x1.go

@@ -189,6 +189,7 @@ func (t *TIM) enableMainOutput() {
 }
 
 type arrtype = uint32
+type psctype = uint32
 type arrRegType = volatile.Register32
 
 const (

src/machine/machine_stm32l0x2.go

@@ -246,6 +246,7 @@ func (t *TIM) enableMainOutput() {
 }
 
 type arrtype = uint32
+type psctype = uint32
 type arrRegType = volatile.Register32
 
 const (

src/machine/machine_stm32l4.go

@@ -532,6 +532,7 @@ func (t *TIM) enableMainOutput() {
 }
 
 type arrtype = uint32
+type psctype = uint32
 type arrRegType = volatile.Register32
 
 const (

src/machine/machine_stm32l5.go

@@ -542,6 +542,7 @@ func (t *TIM) enableMainOutput() {
 }
 
 type arrtype = uint32
+type psctype = uint32
 type arrRegType = volatile.Register32
 
 const (

src/machine/machine_stm32wlx.go

@@ -433,6 +433,7 @@ func initRNG() {
 //----------
 
 type arrtype = uint32
+type psctype = uint32
 type arrRegType = volatile.Register32
 
 const (