Refactor common functions into files

Refactor common functions into files that can be reused by other
platforms. This is just a start, but make it so we can put different
platform init routines in other files and still access the functions
for gpio i2c and filesystem helpers.

Tested:
flash onto a gb200, log output was clean.

```
USB_HUB_RESET_L-O Request to set to 0
USB_HUB_RESET_L-O Set to 0
HMC present in platformSleeping for 100 milliseconds
SGPIO_BMC_EN-O Request to set to 1
SGPIO_BMC_EN-O Set to 1
HMC_BMC_DETECT-O Request to set to 0
HMC_BMC_DETECT-O Set to 0
BMC_EROT_FPGA_SPI_MUX_SEL-O Request to set to 1
BMC_EROT_FPGA_SPI_MUX_SEL-O Set to 1
BMC_12V_CTRL-O Request to set to 1
BMC_12V_CTRL-O Set to 1
PWR_BRAKE_L-O Request to set to 1
PWR_BRAKE_L-O Set to 1
SHDN_REQ_L-O Request to set to 1
SHDN_REQ_L-O Set to 1
SHDN_FORCE_L-O Request to set to 1
SHDN_FORCE_L-O Set to 1
SYS_RST_IN_L-O Request to set to 0
SYS_RST_IN_L-O Set to 0
FPGA_READY_BMC-I GpioEvent is already 1
SEC_FPGA_READY_BMC-I GpioEvent is already 1
EROT_FPGA_RST_L-O Request to set to 1
EROT_FPGA_RST_L-O Set to 1
SEC_EROT_FPGA_RST_L-O Request to set to 1
SEC_EROT_FPGA_RST_L-O Set to 1
Sleeping for 100 milliseconds
FPGA_RST_L-O Request to set to 1
FPGA_RST_L-O Set to 1
FPGA_READY_BMC-I  Waiting to go to assert
FPGA_READY_BMC-I Timeout
FPGA_READY_BMC-I failed to assert
SEC_FPGA_READY_BMC-I  Waiting to go to assert
SEC_FPGA_READY_BMC-I Timeout
SEC_FPGA_READY_BMC-I failed to assert
1e78a100 unbound
1e78a100 bound
1e78a180 unbound
1e78a180 bound
RUN_POWER_EN-O Request to set to 1
RUN_POWER_EN-O Set to 1
SYS_RST_IN_L-O Request to set to 1
SYS_RST_IN_L-O Settingto 1
GLOBAL_WP_BMC-O Request to set to 0
GLOBAL_WP_BMC-O Set to 0
BMC_READY-O Request to set to 1
BMC_READY-O Set to 1
USB_HUB_RESET_L-O Request to set to 1
USB_HUB_RESET_L-O Settingto 1
Platform init complete
```

Change-Id: I7f2134470536d48e1face39075c5fa1d40dc0de7
Signed-off-by: Marc Olberding <molberding@nvidia.com>
diff --git a/meson.build b/meson.build
index 26dbac2..837e289 100644
--- a/meson.build
+++ b/meson.build
@@ -14,7 +14,7 @@
 
 exe = executable(
     'platform',
-    'platform.cpp',
+    ['platform.cpp', 'i2c.cpp', 'gpio.cpp', 'utilities.cpp'],
     dependencies: [gpiodcxx_dep, libsystemd_dep, cli11_dep],
     include_directories: ['.'],
     install: true,
@@ -31,3 +31,5 @@
         {'PLATFORM_NAME': get_option('platform-name')},
     ),
 )
+
+