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>
diff --git a/doc/README.vxworks b/doc/README.vxworks
index 3433e4f..6700e1d 100644
--- a/doc/README.vxworks
+++ b/doc/README.vxworks
@@ -19,7 +19,7 @@
 
 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 @@
 
     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 @@
 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 @@
 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.