fix(BG-Build-OMAP): remove unnecessary backslash

Left in from the previous refactor, these are not needed when
encapsulated by an inline-code wrapper.

Fixes: 6814540 ("refactor(U-Boot): Split K3 and OMAP Build Guide")
Signed-off-by: Randolph Sapp <rs@ti.com>

Author: StaticRocket

source/linux/Foundational_Components/U-Boot/BG-Build-OMAP.rst

@@ -43,23 +43,23 @@ If you did not use a separate object directory:
 
 .. ifconfig:: CONFIG_part_variant in ('AM335X')
 
-   If you used ``O=am335x\_evm`` as your object directory:
+   If you used ``O=am335x_evm`` as your object directory:
 
    .. code-block:: console
 
       $ rm -rf ./am335x_evm
 
 .. ifconfig:: CONFIG_part_variant in ('AM437X')
 
-   If you used ``O=am43xx\_evm`` as your object directory:
+   If you used ``O=am43xx_evm`` as your object directory:
 
    .. code-block:: console
 
       $ rm -rf ./am43xx_evm
 
 .. ifconfig:: CONFIG_part_variant in ('AM57X')
 
-   If you used ``O=am57xx\_evm`` as your object directory:
+   If you used ``O=am57xx_evm`` as your object directory:
 
    .. code-block:: console