Fix clock configuration for LPC1549.

Datasheet (Table 82) says MSEL bits should be 5, and the PSEL bits should
be 1, for the correct FCCO frequency of 288MHz. The current configuration
has FCCO = 144MHz, which is technically out of spec.
Tested on a custom LPC1549 board with crystal oscillator running at 12MHz.

Author: DC37

libraries/mbed/targets/cmsis/TARGET_NXP/TARGET_LPC15XX/system_LPC15xx.c

@@ -73,14 +73,14 @@
 //       <o.0..5> MSEL: Feedback Divider Selection
 //              <i> M = MSEL + 1
 //            <0-31>
-//       <o.5..7> PSEL: Post Divider Selection
+//       <o.6..7> PSEL: Post Divider Selection
 //              <i> Post divider ratio P. Division ratio is 2 * P
 //            <0=> P = 1
 //            <1=> P = 2
 //            <2=> P = 4
 //            <3=> P = 8
 //     </h>
-#define SYSPLLCTRL_Val        0x00000005              // Reset value: 0x000
+#define SYSPLLCTRL_Val        0x00000045              // Reset value: 0x000
 //
 //     <o.0..7>   System AHB Clock Divider (SYSAHBCLKDIV.DIV)
 //            <i> Divides main clock to provide system clock to core, memories, and peripherals.
@@ -156,7 +156,7 @@
 //            <2=> P = 4
 //            <3=> P = 8
 //     </h>
-#define SCTPLLCTRL_Val        0x00000005              // Reset value: 0x000
+#define SCTPLLCTRL_Val        0x00000045              // Reset value: 0x000
 //
 //     <o.0..1> SCT PLL Clock Source Select (SCTPLLCLKSEL.SEL)
 //                   <0=> IRC Oscillator