RP2040: optimize flash/ram occupation

Since we are not using ROM functions here, just keep everything as default as possible

Author: facchinm

targets/TARGET_RASPBERRYPI/TARGET_RP2040/TOOLCHAIN_GCC_ARM/memmap_default.ld

@@ -27,9 +27,15 @@
     #define MBED_CONF_TARGET_BOOT_STACK_SIZE  0x400
 #endif
 
+#if !defined(PICO_FLASH_SIZE_BYTES)
+    /* This value is normally defined by the tools
+       to 0x1000 for bare metal and 0x400 for RTOS */
+    #define PICO_FLASH_SIZE_BYTES  2048k
+#endif
+
 MEMORY
 {
-    FLASH(rx) : ORIGIN = 0x10000000, LENGTH = 2048k
+    FLASH(rx) : ORIGIN = 0x10000000, LENGTH = PICO_FLASH_SIZE_BYTES
     RAM(rwx) : ORIGIN =  0x20000000, LENGTH = 256k
     SCRATCH_X(rwx) : ORIGIN = 0x20040000, LENGTH = 4k
     SCRATCH_Y(rwx) : ORIGIN = 0x20041000, LENGTH = 4k
@@ -70,11 +76,7 @@ SECTIONS
         KEEP (*(.binary_info_header))
         __binary_info_header_end = .;
         KEEP (*(.reset))
-        /* TODO revisit this now memset/memcpy/float in ROM */
-        /* bit of a hack right now to exclude all floating point and time critical (e.g. memset, memcpy) code from
-         * FLASH ... we will include any thing excluded here in .data below by default */
         KEEP (*(.init))
-        *(EXCLUDE_FILE(*libgcc.a: *libc.a:*lib_a-mem*.o *libm.a:) .text*)
         *(.fini)
         /* Pull all c'tors into .text */
         *crtbegin.o(.ctors)
@@ -94,7 +96,6 @@ SECTIONS
     } > FLASH
 
     .rodata : {
-        *(EXCLUDE_FILE(*libgcc.a: *libc.a:*lib_a-mem*.o *libm.a:) .rodata*)
         . = ALIGN(4);
         *(SORT_BY_ALIGNMENT(SORT_BY_NAME(.flashdata*)))
         . = ALIGN(4);
@@ -136,10 +137,6 @@ SECTIONS
 
         *(.time_critical*)
 
-        /* remaining .text and .rodata; i.e. stuff we exclude above because we want it in RAM */
-        *(.text*)
-        . = ALIGN(4);
-        *(.rodata*)
         . = ALIGN(4);
 
         *(.data*)