doc: vxworks: Minor update for clarity

This corrects a typo and updates several places for clarity.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>

doc/README.vxworks

@@ -19,7 +19,7 @@ on PowerPC and ARM, 'bootm' shall be used.
 
 64-bit x86 kernel cannot be loaded as of today.
 
-VxWork 7 on PowerPC and ARM
+VxWorks 7 on PowerPC and ARM
 ---------------------------
 From VxWorks 7, VxWorks starts adopting device tree as its hardware decription
 mechansim (for PowerPC and ARM), thus requiring boot interface changes.
@@ -30,11 +30,11 @@ the ePAPR standard, which is shown below (see ePAPR for more details):
 
     void (*kernel_entry)(fdt_addr, 0, 0, EPAPR_MAGIC, boot_IMA, 0, 0)
 
-For ARM, the calling convention is show below:
+For ARM, the calling convention is shown below:
 
     void (*kernel_entry)(void *fdt_addr)
 
-When booting new VxWorks kernel (uImage format), the parameters passed to bootm
+When booting a VxWorks 7 kernel (uImage format), the parameters passed to bootm
 is like below:
 
     bootm <kernel image address> - <device tree address>
@@ -46,7 +46,7 @@ board-specific address before loading VxWorks. U-Boot supplies its address
 via "bootaddr" environment variable. To check where the bootline should be
 for a specific board, go to the VxWorks BSP for that board, and look for a
 parameter called BOOT_LINE_ADRS. Assign its value to "bootaddr". A typical
-value for "bootaddr" is 0x101200.
+value for "bootaddr" on an x86 board is 0x101200.
 
 If a "bootargs" variable is defined, its content will be copied to the memory
 location pointed by "bootaddr" as the kernel bootline. If "bootargs" is not
@@ -79,7 +79,7 @@ for "e820data" and "e820info" are 0x104000 and 0x104a00. But there is one
 exception on Intel Galileo, where "e820data" and "e820info" should be left
 unset, which assume the default location for VxWorks.
 
-Note since currently U-Boot does not support ACPI yet, VxWorks kernel must
+For boards on which ACPI is not supported by U-Boot yet, VxWorks kernel must
 be configured to use MP table and virtual wire interrupt mode. This requires
 INCLUDE_MPTABLE_BOOT_OP and INCLUDE_VIRTUAL_WIRE_MODE to be included in a
 VxWorks kernel configuration.