Fix various typos, scattered over the code.

Spelling corrections for (among other things):

* environment
* override
* variable
* ftd (should be "fdt", for flattened device tree)
* embedded
* FTDI
* emulation
* controller
diff --git a/doc/README.commands.spl b/doc/README.commands.spl
index ac33273..cb3e0c8 100644
--- a/doc/README.commands.spl
+++ b/doc/README.commands.spl
@@ -10,7 +10,7 @@
 	fdt: exports the FDT
 
 Call is:
-spl export <ftd|atags> [kernel_addr] [initrd_addr] [fdt_addr if fdt]
+spl export <fdt|atags> [kernel_addr] [initrd_addr] [fdt_addr if fdt]
 
 
 TYPICAL CALL
diff --git a/doc/README.marubun-pcmcia b/doc/README.marubun-pcmcia
index d3563a3..0a363b2 100644
--- a/doc/README.marubun-pcmcia
+++ b/doc/README.marubun-pcmcia
@@ -34,7 +34,7 @@
 	ex.	#define CONFIG_PCMCIA_SLOT_A    1
 
     * CONFIG_SYS_MARUBUN_MRSHPC
-	This is MR-SHPC-01 PCMCIA controler base address.
+	This is MR-SHPC-01 PCMCIA controller base address.
 	You should do the setting matched to your environment.
 	ex.  #define CONFIG_SYS_MARUBUN_MRSHPC 0xb03fffe0
 	     ( for MS7722SE01 environment )
diff --git a/doc/README.mxs b/doc/README.mxs
index 6ea73b9..4edf19f 100644
--- a/doc/README.mxs
+++ b/doc/README.mxs
@@ -219,7 +219,7 @@
 
 	   This script expects a working TFTP server containing the file
 	   "u-boot.nand" in it's root directory. This can be changed by
-	   adjusting the "update_nand_full_filename" varible.
+	   adjusting the "update_nand_full_filename" variable.
 
 	   To update the system, run the following in U-Boot prompt:
 
@@ -242,7 +242,7 @@
 
 	   This script expects a working TFTP server containing the file
 	   "u-boot.sb" in it's root directory. This can be changed by
-	   adjusting the "update_nand_firmware_filename" varible.
+	   adjusting the "update_nand_firmware_filename" variable.
 
 	   To update the system, run the following in U-Boot prompt:
 
diff --git a/doc/SPI/README.sandbox-spi b/doc/SPI/README.sandbox-spi
index bb73eaf..dfa845c 100644
--- a/doc/SPI/README.sandbox-spi
+++ b/doc/SPI/README.sandbox-spi
@@ -1,7 +1,7 @@
 Sandbox SPI/SPI Flash Implementation
 ====================================
 
-U-Boot supports SPI and SPI flash emuation in sandbox. This must be enabled
+U-Boot supports SPI and SPI flash emulation in sandbox. This must be enabled
 using the --spi_sf paramter when starting U-Boot.
 
 For example:
diff --git a/doc/SPI/README.ti_qspi_flash b/doc/SPI/README.ti_qspi_flash
index 9064739..5cc1fd0 100644
--- a/doc/SPI/README.ti_qspi_flash
+++ b/doc/SPI/README.ti_qspi_flash
@@ -31,7 +31,7 @@
 Memory mapped read mode
 -----------------------
 In this, SPI controller is configured using configuration port and then
-controler is switched to memory mapped port for data read.
+controller is switched to memory mapped port for data read.
 
 Driver
 ------